Diagnostic Trouble Codes (DTC) (Chevrolet Captiva 1)

• Diagnostic trouble codes P0010, P0011, P0013, P0014, P0020, P0021, P0023, P0024, P0341, P0342, P0343, P0346, P0347, P0348, P0366, P0367, P0368, P0391, P0392, P0393, P2088, P2089, P2090, P2091, P2092, P2093, P2094, and P2095 are not set.
• The engine is running.
• The ECM has determined the camshaft positions.
• DTCs P0008 and P0009 run continuously when the above conditions are met.

• Inspect the engine to identify recent repairs to the mechanical part of the engine. An incorrectly installed secondary camshaft drive circuit can cause this fault code to appear.
• A single faulty variable valve timing actuator or valve cannot cause this DTC. This diagnostic algorithm is designed to detect misalignment between the primary idler sprocket and the secondary camshaft timing chain, or misalignment between the primary idler sprocket and the crankshaft. Either condition can cause both camshafts on the same bank to be out of phase by the same number of degrees.
• The presence of DTCs P0008 and P0009 along with P0016, P0017, P0018 and P0019 indicates a possible primary camshaft timing chain fault and misalignment between both intermediate sprockets and the crankshaft. It is also possible that the crankshaft position sensor is misaligned and not matching the top dead center (TDC) of the crankshaft.
• By comparing the desired and actual camshaft angle values with a scan tool before a fault code is generated, it can be determined whether the fault is specific to one camshaft, one cylinder bank, or is caused by a primary timing issue with the crankshaft.

1. Use a scan tool to clear DTC codes.
2. Allow the engine to warm up to normal operating temperature.
3. Allow the engine to idle for 10 minutes or until a trouble code sets. Use a scan tool to obtain trouble code information; DTC P0008 and P0009 should not be set.

1. Inspect the camshaft drive chains for wear or misalignment.
• If a fault is detected with the camshaft timing chains or tensioners, refer to the "Camshaft Timing Chain Components" section, Part 1C2, "Mechanical part of the HFV6 3.2 L engine."
2. Check if the pulse sensor is installed correctly on the crankshaft.
• If a fault is detected related to the crankshaft, refer to the section "Crankshaft and Main Bearings", Part 1C2, "Mechanical part of the HFV6 3.2 L engine."

• Engine speed is above 80 rpm.
• Ignition voltage 1 in the range of 10-18 V.
• The ECM has commanded the camshaft position actuator solenoid to turn on and off at least once during the ignition cycle.
• DTCs P0010, P0013, P0020, P0023, P2088, P2089, P2090, P2091, P2092, P2093, P2094, and P2095 run continuously when the above conditions are met for more than 1 second.

• The ECM has detected an open, short to ground, or short to supply voltage (B+) in the CMP actuator solenoid circuit while commanding the solenoid OFF.
• The condition is met for more than 4 seconds.

1. Warm up the engine to normal operating temperature, raise the engine speed to 2000 RPM for 10 seconds. DTCs P0010, P0013, P0020, P0023, P2088, P2089, P2090, P2091, P2092, P2093, P2094 and P2095 should not be set.
2. If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.

1. Turn off the ignition, disconnect the harness connector from the corresponding camshaft timing control valve.
2. Turn on the ignition, make sure that the test lamp connected between the ignition circuit contact and ground does not light.

• If the test lamp does not illuminate, check the ignition circuit for a short to ground or an open/high resistance. If no faults are found when testing the circuits and there is an open ignition circuit fuse, check all components connected to the ignition circuit and replace if necessary.
3. Turn off the ignition, connect the test lamp between the control circuit contact and the supply voltage (B+).
4. Turn on the ignition, use a scanning device to send the "on" and "off" commands to the valve timing drive valve. The indicator lamp should light up and go out in accordance with the commands sent.
• If the indicator lamp is constantly on, check the control circuit for a short to ground. If the circuit is OK, replace the ECM.
• If the test lamp does not illuminate, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
5. Turn on the ignition, check for 2.0-3.0 V between the control circuit contact and a reliable ground.
• If the voltage is not in the specified range, replace the ECM controller.
6. If no fault is found when testing all circuits/connections, check or replace the camshaft timing actuator valve.

1. Measure the resistance between the contacts of the camshaft timing control valve, which should be 7-12 Ohms.
• If the resistance is not within the specified range, replace the camshaft timing control valve
2. Check the resistance between each of the contacts and the camshaft timing control valve body. The resistances should be infinitely large.
• If the resistance is less, replace the camshaft timing control valve.

• Before the ECM will report DTCs P0011, P0014, P0021, or P0024, tests P0010, P0013, P0020, P0023, P0341, P0342, P0343, P0346, P0347, P0348, P0366, P0367, P0368, P0391, P0392, P0393, P2088, P2089, P2090, P2091, P2092, P2093, P2094, and P2095 must pass.
• Trouble codes P0016, P0017, P0018, P0019, P0335, P0336, and P0338 are not set.
• Engine speed is above 500 rpm.
• The engine must accelerate so that the variable valve timing drive system is commanded to move from the park position to the desired phase position. This process is a camshaft control cycle. There must be 4-10 camshaft control cycles in total, with the duration of being in the phase offset position for at least 2.5 seconds in each cycle.
• The engine runs for approximately 1.8 seconds.
• DTCs P0011, P0014, P0021, and P0024 run continuously if the above conditions are met for more than 1 second.

• The ECM detects a difference between the desired and actual camshaft angular position that exceeds 5 degrees.

OR

• The ECM detects a difference between the actual and fixed camshaft angular position that exceeds 1 degree.
• This condition persists for more than 4 seconds.

• The condition of the engine oil has a decisive influence on the operation of the camshaft timing drive system.
• This diagnostic code may be set due to low oil level. The engine may require an oil change. The scan tool may also display the Engine Oil Life value (Service life of motor oil).
• Inspect the engine to identify recent repairs to the mechanical part of the engine. This fault code may be caused by incorrect installation of the camshaft, timing control drive, or camshaft drive chain.

Important: The engine oil level and pressure are critical to the proper operation of the variable valve timing drive system. Before continuing with this diagnostic, ensure that the required oil level and pressure are present.

1. Ignition ON, obtain DTC information with a scan tool. Verify that none of the following DTCs are set. DTC P0016, P0017, P0018, P0019, P0335, P0336, P0338, P0341, P0342, P0343, P0346, P0347, P0348, P0366, P0367, P0368, P0391, P0392, P0393, P0521, P0522, or P0523.
• If any of the listed fault codes are set, refer to the information for the corresponding code for further diagnostics.
2. Engine idling. Command the suspected camshaft actuator to move from 0 to 40 degrees and back to zero while observing the corresponding CMP angle deviation parameters with a scan tool. The CMP angle deviation should be within 2 degrees for each position as commanded.
3. If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.

1. Turn off the ignition, disconnect the harness connector from the corresponding camshaft timing control valve.
2. Turn on the ignition, make sure that the test lamp connected between the ignition circuit contact and a reliable ground does not light.

Important: The ignition circuit supplies voltage to other components. It is necessary to ensure that all circuits are checked for shorts to ground and that all components that are part of the ignition circuit are checked for shorts.

• If the test lamp does not illuminate, check the ignition circuit for a short to ground or an open/high resistance. If no faults are found when testing the circuits and there is an open ignition circuit fuse, check all components connected to the ignition circuit and replace if necessary.
3. Turn off the ignition, connect the test lamp between contact 2 of the control circuit and B+.
4. Turn on the ignition, use a scanning device to send the "on" and "off" commands to the valve timing drive valve. The indicator lamp should light up and go out in accordance with the commands sent.
• If the indicator lamp is constantly on, check the control circuit for a short to ground. If the circuit is OK, replace the ECM.
• If the test lamp does not illuminate, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
5. Remove the camshaft timing control valve. Inspect the camshaft timing control valve and installation location and check for the following faults:
• Torn, clogged, incorrectly installed or missing camshaft timing actuator valve screens.
• Engine oil leaks near the seat surfaces of the valve seals of the camshaft timing control drive. Make sure that there are no scratches on the seat surfaces of the camshaft timing control valve.
• Oil leakage at the camshaft timing control valve connector.
• If a malfunction is detected, replace the camshaft timing control valve.
6. If no fault is found when testing all circuits/connections, check or replace the camshaft timing actuator valve.

1. Test for the presence of 7-12 Ohm resistance between the contacts of the camshaft timing control valve.
• If the resistance is not within the specified range, replace the camshaft timing control valve
2. Check the resistance between each of the contacts and the valve body of the camshaft timing control drive. The resistances should be infinitely large.
• If the resistance is less, replace the camshaft timing control valve.

• Before the ECM can set DTCs P0016, P0017, P0018, or P0019, DTCs P0010, P0011, P0013, P0014, P0020, P0021, P0023, P0024, P0335, P0336, P0338, P0341, P0342, P0343, P0346, P0347, P0348, P0366, P0367, P0368, P0391, P0392, P0393, P2088, P2089, P2090, P2091, P2092, P2093, P2094, and P2095 must not be detected.
• The engine runs for more than 5 seconds.
• Engine coolant temperature between 0-95°C (32-203°F).
• Calculated engine oil temperature is below 120°C (248°F).
• DTCs P0016, P0017, P0018, and P0019 will set continuously when the above conditions are met for approximately 10 minutes.

• The ECM detects one of the following faults:
• The ECM detects a misalignment between the camshaft and crankshaft positions.
• The camshaft is too far ahead of the crankshaft.
• The camshaft is too far behind the crankshaft.
• The ECM detects a difference between the actual and fixed camshaft angular position that exceeds 1 degree.
• This condition persists for more than 4 seconds.

• Inspect the engine to identify recent repairs to the mechanical part of the engine. This fault code may result from incorrect installation of the camshaft, timing control drive, camshaft sensor, crankshaft sensor, or camshaft drive chain.
• This DTC may set if the variable valve timing actuator is in the maximum advance or retard position.
• The presence of DTCs P0008 and P0009 along with P0016, P0017, P0018 and P0019 indicates a possible primary camshaft timing chain fault and misalignment between both intermediate sprockets and the crankshaft. It is also possible that the crankshaft position sensor is misaligned and not matching the top dead center (TDC) of the crankshaft.
• By comparing the desired and actual camshaft angle values with a scan tool before a fault code is generated, it can be determined whether the fault is specific to one camshaft, one cylinder bank, or is caused by a primary timing issue with the crankshaft.

1. Ignition ON, obtain DTC information with a scan tool. Verify that none of the following DTCs are set. DTC P0010, P0013, P0020, P0023, P0335, P0336, P0338, P0341, P0342, P0343, P0346, P0347, P0348, P0366, P0367, P0368, P0391, P0392, P0393, P2088, P2089, P2090, P2091, P2092, P2093, P2094, or P2095.
• If any of the listed fault codes are set, refer to the information for the corresponding code for further diagnostics.
2. Allow the engine to idle at normal operating temperature for 10 minutes. DTCs P0016, P0017, P0018, or P0019 should not set.
• If diagnostic trouble codes are set, check the following:
• Correct installation of camshaft sensors.
• Correct installation of the crankshaft sensor.
• Condition of the camshaft drive chain tensioner.
• Incorrectly installed camshaft drive chain.
• Excessive free play in the camshaft drive chain.
• The camshaft drive chain is skipping teeth.
• The crankshaft pulse sensor is offset from the top dead center of the crankshaft.
3. If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
Ignition voltage	P0030, P0036, P0050, P0056	P0030, P0036, P0050, P0056	-	P0135, P0141, P0155, P0161
HO2S Heater Control Circuit Sensor 1	P0031, P0051	P0030, P0050	P0032, P0052	P0135, P0141, P0155, P0161
HO2S Heater Control Circuit Sensor 2	P0037, P0057	P0036, P0056	P0038, P0058	P0135, P0141, P0155, P0161

• Signal chain
• Low Reference Circuit
• Ignition voltage circuit
• Heater control circuit

• Ignition voltage within 10.5-18 V.
• Engine speed is above 80 rpm.
• The oxygen sensor (HO2S) heater is commanded on and off at least once per ignition cycle.
• The fault codes are issued continuously if the above conditions are met for 1 second.

• Ignition voltage within 10.5-18 V.
• Engine speed is above 80 rpm.
• The oxygen sensor (HO2S) heater is commanded on and off at least once per ignition cycle.
• The oxygen sensor (HO2S) is at operating temperature.
• The fault codes are issued continuously if the above conditions are met for 1 second.

• If the fault is intermittent, move the affected harnesses and connectors with the engine running while monitoring the circuit status of the affected component with a scan tool. The circuit status parameter changes from OK to Indeterminate (Not defined) to Fault (Faulty), if the condition is related to a circuit or connector. The control module (ODM) information is located in the module data list.
• An open fuse in the oxygen sensor control heater circuit may be related to the heating element in one of the sensors. This fault may not be present until the sensor has been in operation for some time. If there is no fault in the heater circuit, then the current in each of the heaters should be checked with a digital multimeter to determine if the open fuse is caused by the heating element in one of the heaters. Check to see if the probe lead or harness is making contact with exhaust system components.

1. Turn ignition off, disconnect the harness connector at the appropriate heated oxygen sensor (HO2S).
2. Turn on the ignition, make sure that the test lamp lights between the ignition circuit contact and a reliable ground.

Important: The ignition circuit supplies voltage to other components. It is necessary to ensure that all circuits are checked for shorts to ground and that all components that are part of the ignition circuit are checked for shorts.

• If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If no faults are found when testing the circuits and the ignition circuit fuse is open, check all components connected to the ignition circuit 1 and replace if necessary.
3. Turn off the ignition, connect the test lamp between the heater control circuit contact and the "B+" voltage. The test lamp should not light.
• If the test lamp is always on, check the control circuit for a short to ground. If no fault is found when testing the circuit/connections, replace the ECM.

Important: The HO2S heater control circuit is connected to a voltage source inside the ECM. Normal voltage for the control circuit is between 2.0 and 3.0 volts.

4. Start the engine at idle speed and check whether the indicator lamp lights continuously or flashes.
• If the test lamp does not illuminate at all, test the control circuit for a short to a live wire or an open/high resistance. If no fault is found when testing the circuit/connections, replace the ECM.
5. Turn on the ignition, test for 2.0 - 3.0 volts between the control circuit terminal "D" and ground.
• If the voltage is not within the specified range, replace the ECM.
6. If no fault is found when testing all circuits/connections, then test or replace the HO2S.

1. Turn off the ignition, disconnect the harness connector from the corresponding oxygen sensor (with electric heater) (HO2S).
2. Check the resistance of the oxygen sensor heater, which should be 3-35 Ohms.
• If the resistance is not within the specified range, replace the oxygen sensor.

• Signal chain
• Low Reference Circuit
• Ignition voltage circuit
• Heater control circuit

• Ignition voltage within 10.5-18 V.
• Engine speed is above 80 rpm.
• The oxygen sensor (HO2S) heater is commanded on and off at least once per ignition cycle.
• The fault codes are issued continuously if the above conditions are met for 1 second.

• If the fault is intermittent, move the affected harnesses and connectors with the engine running while monitoring the circuit status of the affected component with a scan tool. If the circuit status parameter changes from "OK" (normal) or "Indeterminate" (not defined) on "Fault" (out of order), there is a fault with the circuit or connector. The control module (ODM) information is in the module data list.
• An open fuse in the oxygen sensor control heater circuit may be related to the heating element in one of the sensors. This fault may not be present until the sensor has been in operation for some time. If there is no fault in the heater circuit, then the current in each of the heaters should be checked with a digital multimeter to determine if the open fuse is caused by the heating element in one of the heaters. Check to see if the probe lead or harness is making contact with exhaust system components.

• Diagnostic trouble codes P0112, P0113, P0117, P0118 are not set.
• The engine is running.
• The ignition has been off for more than 10 hours.
• The Engine Coolant Temperature (ECT) sensor parameter at engine start is between -30°C and +45°C (-22°F and +113°F).
• The difference between the ECT sensor and the intake manifold air temperature (IAT) sensor is less than 8°C (14°F) at engine start.
• DTCs P0053 and P0059 will set once per drive cycle when the above conditions are met.

• Warm up the engine to operating temperature. With the engine running, observe the HO2S heater parameter with a scan tool. The value should vary from approximately 2 amps to just above 1 amp.
• With the engine running at operating temperature, observe the HO2S heater parameter with a scan tool and wiggle the associated wiring and connectors.
• If the parameter changes under such influence, repair the wiring harness or connector.

1. Turn ignition off, disconnect the wiring harness connector from the appropriate HO2S sensor.
2. Turn on the ignition, make sure that the test lamp lights when connected between the voltage circuit contact "B+" and a reliable ground.
• If the test lamp does not illuminate, test the "B+" voltage circuit for a short to ground or an open/high resistance. If the circuits are OK but the "B+" fuse is blown, replace the HO2S.
3. Turn ignition off, verify that the test lamp does not illuminate between the low control circuit terminal of the appropriate HO2S and the "B+" voltage circuit.
• If the test lamp is illuminated, test the low control circuit for a short to ground.
4. Connect a test lamp between the low level control circuit terminal of the appropriate HO2S heater and the "B+" voltage circuit terminal.
5. When the engine is running, the indicator lamp should be continuously lit or flashing.
• If the test lamp does not remain on or flash, test the low control circuit for a short to voltage and an open/high resistance. If the circuit is OK, replace the controller.
6. Turn ignition off, connect a 30A fused jumper wire between the "B+" circuit terminal and the heater low control circuit on the appropriate HO2S.
7. With the engine running, use a scan tool to verify that the appropriate HO2S heater parameter reads 0.0 A.
• If the scan tool does not indicate 0.0 amps, test the heater "B+" circuit and the low control circuit for resistance greater than 3 ohms. If the circuit is good, replace the controller.
8. If all circuits are normal, replace the appropriate HO2S sensor.

• Throttle position (TP) sensor.
• Intake Air Temperature (IAT).
• Engine speed.

• DTCs P2101 or P2119 are not set.
• The engine is running.
• Trouble code P0068 runs continuously when the above conditions are met.

1. Check the following:
• No cracks, kinks, and secure connections of vacuum hoses as shown on the vehicle emission control information label.
• Check the hoses thoroughly for leaks and blockages.
• Air leak in the throttle body mounting area and intake manifold sealing surfaces.
2. Check the throttle body for the following faults:
• Loose or damaged throttle valve.
• Throttle shaft failure.
• Any damage to the throttle body.
• If any of these conditions exist, replace the throttle body assembly.
3. Connect the scan tool and wait until the engine reaches operating temperature. Observe the MAF sensor parameters.
4. Create a protocol with a list of engine data by following the steps below.
• Start the engine at idle speed.
• Slowly increase engine speed to 3000 rpm, then return to idle.
• Complete the protocol creation and view the data.
• View the MAF/TP sensor parameters frame by frame. The MAF/TP sensor parameters should change smoothly and continuously as the engine speed increases and returns to idle.
If the MAF/TP sensor readings do not change continuously and smoothly as the engine speed increases and returns to idle, locate the faulty sensor and replace it.

Chain	Short circuit with "ground"	High resistance	Breakup	Short circuit to live wire	Signal parameters
Ignition voltage 1	P0102	P0101	P0100	-	P0101
MAF sensor signal	P0102	P0101	P0103	P0103	P0101
Low reference voltage	-	P0101, P0103	P0103	-	P0101

• The engine is running.
• Ignition voltage 1 exceeds 10.5 V.
• DTC P0100 runs continuously if the above conditions are met for more than 1 second.

• Before the ECM controller can detect faults with codes P0102 or P0103, it is necessary that no faults corresponding to codes P0121, P0122, P0123, P0221, P0222, P0223, P0336 and P0338 are detected.
• The engine is running.
• Engine speed exceeds 320 rpm.
• Ignition voltage 1 is greater than 7.5 V.
• DTCs P0102 and P0103 run continuously if the above conditions are met for less than 1 second.

• The ECM detects that the MAF sensor signal is outside the specified range of calculated mass air flow values.
• This condition lasts for 4 seconds.

• The ECM detects that the MAF sensor signal is less than -11.7 grams per second.
• This condition persists for more than 4 seconds.

• The ECM detects that the MAF sensor signal is greater than 294 grams per second.
• This condition persists for more than 4 seconds.

• Inspect the MAF sensor harness to see if it is too close to the following components:
• Wiring or secondary windings of ignition coils
• Any solenoids
• Any relay
• Any motors
• Acceleration from a stop at wide open throttle (WOT) should cause the MAF sensor reading on the scan tool to increase rapidly. This increase should range from 3-10 g/s at idle to 150 g/s or more during a 1-2 shift. If no increase is observed, then the intake or exhaust airflow should be checked for obstructions.
• Check whether the sensitive elements of the MAF sensor are dirty or whether water is penetrating into them. If the sensor is dirty, clean it. If it is impossible to clean the sensor, replace it.
• High resistance can lead to poor engine performance even before the diagnostic fault code is set.

1. Leave the engine running at idle for 1 minute, and use the scanning device to get information about diagnostic trouble codes. The codes P0100, P0102, and P0103 should not be set.
2. If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.

1. Turn off ignition, disconnect harness connector from MAF sensor.

Note: DO NOT use the low signal test circuit at the component harness connector for this test. Damage to this control unit may result in increased current.

2. Turn on the ignition, make sure that the test lamp connected between the ignition circuit contact and ground does not light.
• If the test lamp does not illuminate, check the ignition circuit for a short to ground or an open/high resistance. If no faults are found when testing the circuits and there is an open ignition circuit fuse, check all components connected to the ignition circuit and replace if necessary.
3. Check that the test lamp connected between the "B+" voltage and the ground circuit contact is lit.
• If the test lamp does not light, repair the open/high resistance in the ground contact circuit.
4. Using a scan tool, check if the MAF sensor voltage is greater than 4.8 volts.
• If voltage is less than specified, test signal circuit for short to ground. If circuit/connections test normal, replace ECM.
5. Connect a jumper wire with a 3 A fuse between the signal circuit terminal and the ground circuit terminal. Using a scan tool, verify that the MAF sensor voltage is less than 0.10 V.
• If the voltage is greater than the specified value, check the signal circuit for a short circuit to a live wire or for open / high resistance. If no fault is detected during circuit / connection testing, replace the ECM controller.
6. If no fault is found when testing all circuits/connections, replace the MAF sensor.

Chain	Short circuit with "ground"	High resistance	Breakup	Short circuit to live wire	Signal parameters
Ignition voltage 1	P0102	P0101	P0100	-	P0101
MAF sensor signal	P0102	P0101	P0103	P0103	P0101
Low reference voltage	-	P0101, P0103	P0103	-	P0101

• Before the ECM will report DTC P0101, tests P0100, P0102, P0103, P0121, P0122, P0123, P0221, P0222, P0223, P0335, P0336, and P0338 must pass.
• DTC P2176 is not set.
• Engine speed is above 320 rpm.
• The MAF sensor signal shows more than 11 g/s.
• Ignition voltage is greater than 10.5 volts.
• The ECM detects greater than 150 crankshaft revolutions.
• DTC P0101 runs continuously if the above conditions are met for more than 2 seconds.

• The ECM detects that the MAF sensor signal is outside the specified range of calculated mass air flow values.
• This condition lasts for 4 seconds.

• Inspect the MAF sensor harness to see if it is too close to the following components:
• Wiring or secondary windings of ignition coils
• Any solenoids
• Any relay
• Any motors
• Dirty or worn air filter element.
• Water entering the intake system.
• Vacuum leak.
• Brake booster leak.
• Malfunction in the crankcase ventilation system.
• Clogged or damaged air duct.
• Acceleration from a stop at wide open throttle (WOT) should cause the MAF sensor reading on the scan tool to increase rapidly. This increase should range from 3-10 g/s at idle to 150 g/s or more during a 1-2 shift. If no increase is observed, then the intake or exhaust airflow should be checked for obstructions.
• Check whether the sensitive elements of the MAF sensor are dirty or whether water is penetrating into them. If the sensor is dirty, clean it. If it is impossible to clean the sensor, replace it.
• High resistance can lead to poor engine performance even before the diagnostic fault code is set.

1. Let the engine idle for 1 minute, get the diagnostic trouble codes with a scan tool. The code P0101 should not be set.
2. If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.

1. Check the following:
• Engine vacuum leak
• Air leak in the intake air duct between the mass air flow (MAF) sensor and the throttle body
• Clogged or damaged air intake duct
• An object is blocking the MAF sensor air intake
• Clogged air filter element.
• Clogged throttle body or carbon deposits around the throttle body
• The engine oil dipstick is not installed in place
• The engine oil filler cap is loose or missing
• Crankcase overfilling
• If any of the above faults are detected, they should be corrected.
2. Turn off ignition, disconnect harness connector from MAF sensor.

Note: DO NOT use the low signal test circuit at the component harness connector for this test. Damage to this control unit may result in increased current.

3. Turn on the ignition, make sure that the test lamp connected between the ignition circuit contact and ground does not light.
• If the test lamp does not illuminate, check the ignition circuit for a short to ground or an open/high resistance. If no faults are found when testing the circuits and there is an open ignition circuit fuse, check all components connected to the ignition circuit and replace if necessary.
4. Check that the test lamp connected between the "B+" voltage and the ground circuit contact is lit.
• If the test lamp does not light, repair the open/high resistance in the ground contact circuit.
5. Using a scan tool, check if the MAF sensor voltage is greater than 4.8 volts.
• If voltage is less than specified, test signal circuit for short to ground. If circuit/connections test normal, replace ECM.
6. Connect a jumper wire with a 3 A fuse between the signal circuit terminal and the ground circuit terminal. Using a scan tool, verify that the MAF sensor voltage is less than 0.10 V.
• If the voltage is greater than the specified value, check the signal circuit for a short circuit to a live wire or for open / high resistance. If no fault is detected during circuit / connection testing, replace the ECM controller.
7. If no fault is found when testing all circuits/connections, replace the MAF sensor.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
IAT sensor signal	P0112	P0111, P0113	P0113?	P0111
Low reference voltage	-	P0111, P0113	P0113?	P0111
? Internal damage may occur in the ECM or sensor if the circuit is shorted to "B+" voltage.

• Before the ECM will report a P0111 fault, the P0101 tests must pass.
• Trouble codes P0112, P0113, P0116, P0117, P0118, P0119, P0125, and P0128 are not set.
• Engine coolant temperature (ECT) at startup is below 65.4°C (149.7°F).
• ECT temperature is above 75°C (167°F).
• The vehicle speed is below 10 km/h (6.3 mph).
• DTC P0111 runs continuously if the above conditions are met for more than 2 seconds.

• Before the ECM will report a P0111 fault, the P0101 tests must pass.
• Trouble codes P0112, P0113, P0116, P0117, P0118, P0119, P0125, and P0128 are not set.
• Engine coolant temperature (ECT) at startup is below 65.4°C (149.7°F).
• The vehicle speed is greater than 60 km/h (37.4 mph).
• MAF sensor value in the range of 11-42 g/s.
• Fuel Cut-Off during Engine Brake (DFCO) is not activated.
• DTC P0111 runs continuously if the above conditions are met for more than 2 seconds.

• The engine running time exceeds 3 minutes.
• The engine idles for more than 10 seconds.
• Diagnostic tests are performed continuously when the above conditions are met.

• The ECM detects that the intake air temperature has increased by less than 4°C (7°F) while performing the idle test.
• The condition is met for 16 seconds continuously or 4 times longer than 4 seconds each. OR
• The ECM detects that the intake air temperature has increased by less than 4°C (7°F) during the speed stability test.
• The fault exists for more than 28 seconds or occurs more than 7 times with a duration of more than 4 seconds in each case.

• The ECM detects that the intake air temperature is greater than 132°C (270°F) for more than 4 seconds.

• The ECM detects that the intake air temperature is less than -42°C (-43.6°F) and within 3°C (5°F) of that value when the air flow increases by more than 999 grams. The scan tool is limited to -40°C (-40°F) and the diagnostic procedure uses -39°C (-38°F) to identify an intake air temperature fault.
• This condition persists for more than 4 seconds.

• If the vehicle has been parked overnight, the IAT and ECT sensor readings should not differ by more than 3°C (5°F).
• A high resistance in the IAT sensor signal circuit or the IAT sensor low reference circuit may cause a DTC to set.

1. Turn off ignition, disconnect MAF/IAT sensor.
2. Turn on the ignition, make sure that the parameter "IAT sensor" has a value of -40°C (-40°F).
• If greater than -40°C (-40°F), test the IAT sensor signal circuit for a short to ground. If the circuit/connections test normal, replace the ECM.
3. Turn off the ignition, remove the fuse through which the "B+" voltage is supplied to the ECM.

Note: DO NOT use a test lamp to check for continuity. Damage to this control unit may result in increased current.

4. Check for less than 5 ohms of resistance between the low reference circuit terminal and a good ground.
• If resistance is greater than 5 ohms, test the low reference circuit for an open/high resistance, or a short to a live wire. If no fault is found when testing the circuit/connections, replace the ECM.
5. Install a fuse through which the "B+" voltage is supplied to the ECM controller.
6. Turn ignition on, connect a jumper wire with a 3 A fuse between the signal circuit terminal and the low reference circuit terminal. Verify that the IAT sensor parameter is greater than 132°C (270°F).

Important: If the IAT sensor signal circuit is shorted to a live wire, the IAT sensor may be damaged.

• If less than 132°C (270°F), then check the IAT sensor signal circuit for a live wire fault or for open / high resistance. If no fault is detected during circuit / connection testing, replace the ECM controller.
7. If no fault is found when testing all circuits/connections, check or replace the MAF/IAT sensor.

1. Turn off ignition, disconnect harness connector from IAT sensor.

Important: You can use a thermometer to check the sensor outside the vehicle.

2. Test the IAT sensor by varying its temperature and simultaneously measuring the electrical resistance of the sensor. Compare the results with the values given in the table Resistance vs. Temperature. Intake Air Temperature Sensor (IAT). The measured resistances should not differ from the required values by more than 5 percent.
• If the resistances differ by more than 5 percent, the IAT sensor must be replaced.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
ECT sensor signal	P0117	P0118, P0119	P0118, P0119?	P0116?
Low reference voltage	-	P0118, P0119	P0118, P0119?	P0116?
? Internal damage may occur to the ECM or ECT sensor if the circuit is shorted to B+.

ECT sensor	ECT sensor resistance	ECT signal voltage
Cold	High	High
Warm	Low	Low

• Before the ECM will report DTC P0116, the P0101 test must pass.
• Trouble codes P0117, P0118, and P0119 are not set.
• The engine running time in the previous ignition cycle was more than 10 minutes.
• The total air mass in the previous ignition cycle exceeds 4000 grams.
• The minimum IAT temperature during the previous ignition cycle is between -30°C and +2°C (-22°F... 36°F).
• When the ignition is turned on, the IAT temperature is from -30°C to 2°C (-22°F... +36°F).
• DTC P0116 sets once per ignition cycle when the above conditions are met.

• Before the ECM will report DTC P0116, test P0101 must pass.
• Trouble codes P0117, P0118, and P0119 are not set.
• The ECT temperature at the previous engine shutdown was greater than 85°C (185°F).
• The ECM detects an expected increase in intake air temperature when the ECM was powered down in the previous ignition cycle. An open hood or strong wind may prevent the intake air temperature from rising.
• Block heater not detected.
• DTC P0116 sets once per ignition cycle when the above conditions are met.

• The ECM detects that the difference between the engine coolant temperature and the intake air temperature at ignition ON is more than 10°C (18°F) from the difference recorded during the previous ignition cycle when all required conditions were met.

OR

• The ECM detects that the IAT at ignition ON is within the calibrated range of the ECT and IAT recorded in the previous ignition cycle, but the ECT is outside 30°C (54°F) of the calibrated range.
• Any of these conditions persists for more than 4 seconds.

• Test the ECT and IAT sensors at different temperature levels to determine whether the sensors may have a systematic error. A sensor that gives an erroneous reading may cause a diagnostic fault code to appear or the engine's performance to deteriorate. Refer to the temperature-resistance relationships for the engine coolant temperature sensor (ECT) and for the intake air temperature sensor (IAT).
• If the vehicle has been parked overnight, the IAT and ECT sensor readings should not differ by more than 3°C (5°F).
• After starting a cold engine, the ECT sensor temperature should rise continuously and stabilize when the thermostat opens.
• High resistance in the ECT or IAT sensor circuits may cause a DTC to set.
• A short to ground or supply voltage by a conductive substance or liquid may cause this trouble code to set. Inspect the ECT sensor for signs of liquid intrusion into the connector housing.

1. Verify that the following DTCs are not set: P0101, P0117, P0118, and P0119.
• If any of these codes are set, you should refer to the information for that code.
2. Check the coolant level. Check the correct functioning of the cooling system.
• If it is suspected that there is a fault in the cooling system, then refer to the section Part 1D1. "Engine cooling".
3. Subject the vehicle to the conditions that set the DTC. You can also subject the vehicle to the conditions that were observed in the Freeze Frame/Failure Records buffer. DTC P0116 should not set.

1. Turn off ignition, disconnect ECT sensor.
2. Turn on the ignition, make sure that the parameter "ECT sensor" has a value of -40°C (-40°F).
• If greater than -40°C (-40°F), test the ECT sensor signal circuit for a short to ground. If the circuit/connections test normal, replace the ECM.
3. Turn off the ignition, remove the fuse through which the "B+" voltage is supplied to the ECM controller circuit contact.

Note: DO NOT use a test lamp to check for continuity. High current may damage the controller.

Important: The controller or sensor may be damaged if the circuit is shorted to the positive terminal of the battery.

4. Check for less than 5 ohms of resistance between the low reference circuit terminal and a good ground.
• If resistance is greater than 5 ohms, test the low reference circuit for an open/high resistance, or a short to a live wire. If no fault is found when testing the circuit/connections, replace the ECM.
5. Turn off the ignition, install a fuse through which the "B+" voltage is supplied to the ECM controller circuit contact.
6. Turn the ignition on, connect a 3-amp fused jumper wire between the signal circuit and the ECT sensor low reference circuit and verify that the parameter "ECT sensor" has a value greater than 142°C (288°F).
• If less than 143°C (289°F), then check the signal circuit of the ECT sensor for a short circuit to a live wire or for open / high resistance. If no fault is detected during circuit / connection testing, replace the ECM controller.
7. If no fault is found when testing all circuits/connections, check or replace the ECT sensor.

1. Turn ignition off, disconnect the engine coolant temperature (ECT) sensor harness connector.

Important: You can use a thermometer to check the sensor outside the vehicle.

2. Check the ECT sensor by changing its temperature and simultaneously measuring the electrical resistance of the sensor. Compare the results with the values given in the table Resistance vs. Temperature. Intake Air Temperature Sensor (IAT). The measured resistances should not differ from the required values by more than 5 percent.
• If the resistances differ by more than 5 percent, the ECT sensor must be replaced.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
ECT sensor signal	P0117	P0118, P0119	P0118, P0119?	P0116
Low reference voltage	-	P0118, P0119	P0118, P0119?	P0116
? Damage to the ECM or sensor may occur if the circuit is shorted to "B+" voltage.

ECT sensor	ECT sensor resistance	ECT signal voltage
Cold	High	High
Warm	Low	Low

• The engine is running.
• Intake air temperature (IAT) at startup is less than 72°C (161°F).

OR

• Initial intake air temperature (IAT) is greater than 72°C (161°F).
• Engine running time is more than 59 seconds.
• The diagnostic check is performed continuously when the above conditions are met.

• The ignition is on or the engine is running.
• The diagnostic trouble code is set continuously when the above condition is met.

• The ignition is on or the engine is running.
• The diagnostic trouble code is set continuously when the above condition is met.

• Test the ECT sensor at various temperature levels to evaluate whether the sensor has a systematic error. An erratic sensor may cause a diagnostic trouble code or poor engine performance. Refer to the temperature-resistance relationship for the engine coolant temperature (ECT) sensor.
• If the vehicle has been parked overnight, the IAT and ECT sensor readings should not differ by more than 3°C (5°F).
• After starting a cold engine, the ECT sensor temperature should rise continuously and stabilize when the thermostat opens.
• High resistance in the ECT or IAT sensor circuits may cause a diagnostic trouble code to set.

1. Turn off ignition, disconnect ECT sensor.
2. Turn on the ignition, make sure the ECT sensor parameter is?40°C (?40°F).
• If the voltage is greater than specified, check the signal circuit for a short to ground. If no fault is found when testing the circuit/connections, replace the ECM.

Note: DO NOT use a test lamp to check for continuity. Damage to this control unit may result in increased current.

Important:

• The ECT sensor shares a low reference circuit with other sensors. If the low reference circuit, which is an internal circuit to the ECM, is open, it will be possible to measure 1-5 volts in the circuit due to the feed through the other sensors.
• The controller or sensor may be damaged if the circuit is shorted to B+.

3. Check for less than 5V between the low reference circuit terminal and a good ground.
• If the voltage exceeds the required range, repair the short circuit of the low reference signal circuit to B+ and replace the ECM.
4. Turn off the ignition, remove the fuse through which the "B+" voltage is supplied to the ECM.
5. Check for less than 5 ohms of resistance between the low reference circuit terminal and a good ground.
• If resistance is greater than the specified range, test the low reference circuit for an open/high resistance. If circuit/connections test normal, replace the ECM.
6. Install a fuse through which the "B+" voltage is supplied to the ECM controller.
7. Turn ignition on, connect a 3-amp fused jumper wire between the signal circuit terminal and the low reference circuit terminal. Verify that the ECT sensor parameter is greater than 142°C (288°F).
• If the voltage is less than the specified range, then check the signal circuit for a short circuit to a live wire or for open / high resistance. If no fault is detected during circuit / connection testing, replace the ECM controller.
8. If no fault is found when testing all circuits/connections, check or replace the ECT sensor.

1. Turn ignition off, disconnect the engine coolant temperature (ECT) sensor harness connector.

Important: You can use a thermometer to check the sensor outside the vehicle.

2. Check the ECT sensor by varying its temperature and simultaneously measuring the electrical resistance of the sensor. Compare the readings with the values in the table "Resistance vs. Temperature" - Intake Air Temperature (IAT) sensor. Make sure that the resistance corresponds to the specified value with a tolerance of 5 percent.
• If the resistances differ by more than 5 percent, the ECT sensor must be replaced.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
Reference voltage 5V	P0122, P0222, P2127	P0121, P0122, P0221, P2101, P2176	P0223, P2101, P2138, P2128, P2119	P0121, P0221
TP sensor signal 1	P0122	P0122	P0123	P0121
TP sensor signal 2	P0222	P0222	P0223, P0638, P2128, P2138	P0221
Low reference voltage	-	P0121, P0123, P0221, P0223, P2176	P0123, P02231?	P0121, P0221
? The ECM or TP sensor may be internally damaged if the circuit is shorted to B+.

• Ignition voltage 1 is greater than 7 volts.
• TP 1 sensor voltage in the range of 0.17-4.6 V.
• DTC P0121 runs continuously when the above conditions are met.

• Ignition on, engine off or running.
• Ignition voltage 1 is greater than 7 V.
• DTC P0122 runs continuously when the above conditions are met.

• Ignition voltage 1 is greater than 7 volts.
• TP 2 sensor voltage in the range of 0.15-4.8 V.
• DTC P0221 runs continuously when the above conditions are met.

1. Turn ignition on, check DTC data with scan tool.
2. Turn on the engine, use a scanning device to determine the voltage for sensors TP 1 and 2. For sensor TP 1 it should be in the range of 0.17-4.6 V, and for sensor TP 2 in the range of 0.15-4.8 V.
3. Determine the parameters for sensors TP 1 and 2 during the following tests:
• Quickly press the accelerator pedal from the starting position to the wide open throttle (WOT) position and release the pedal. Repeat the procedure several times.
• Slowly press the accelerator pedal until the throttle valve is fully open and then slowly return the pedal to the closed throttle valve position. Repeat the procedure several times. The parameter for TP sensors 1 and 2 should have the value Agree.
4. Obtain trouble code information using a scan tool. DTCs P0121, P0122, P0123, P0221, P0222, and P0223 should not be set.

1. Turn off ignition, disconnect throttle body harness connector.
2. Turn ignition off, test for 5 ohms or less between the low reference circuit and ground.
• If the resistance is greater than the specified value, check the low reference signal for a short circuit to the live wire or for open / high resistance. If no fault is detected during circuit / connection testing, replace the ECM controller.
3. Turn on the ignition; using a load, check for 4.8-5.2 V between a test lamp connected to the 5-volt reference signal circuit and ground.

Important: The 5-volt reference circuits are internally and externally connected to the ECM. Other component DTCs may be set. If other DTCs are set, use the electrical diagram to identify the appropriate circuits and components.

• If less than 4.8 V, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuits and connectors are OK, replace the ECM.
• If voltage is greater than 5.2 V, test 5 V reference circuit for short to supply voltage. If circuit/connections test normal, replace ECM.
4. Turn on the ignition, check that the voltage of each TP sensor is less than 0.3 volts.
• If the voltage of the TP sensor exceeds 0.3 V, then check the corresponding signal circuit for a short circuit to the live wire. If no fault is detected during circuit / connection testing, replace the ECM controller.
5. Connect a jumper wire with a 3 A fuse between the 5-volt reference signal circuit and the signal circuit of each of the TR sensors.
6. Using a scan tool, determine the voltage of each of the TR sensors when connected to 5 volts. The voltage of both TR sensors should be 5.00 V.
• If the TP sensor voltage is less than 5.00 V, test the appropriate signal circuit for a short to ground or an open/high resistance. If no fault is found when testing the circuit/connections, replace the ECM.
7. Turn off the ignition, remove the ECM fuse.

Note: DO NOT use a test lamp to check for continuity. Damage to this control unit may result in increased current.

Important: The controller or sensor may be damaged if the circuit is shorted to the positive terminal of the battery.

8. Test for 5 ohms or less resistance between the low reference circuit and ground.
• If resistance is greater than 5 ohms, test the low reference circuit for an open/high resistance, or a short to a live wire. If no fault is found when testing the circuit/connections, replace the ECM.
9. If no fault is found when testing all circuits/connections, check or replace the throttle body assembly.

• The DTC diagnostic trouble codes P0112, P0113, P0117, P0118, P0480, P0481, P0691, P0692, P0693, and P0694 are not set.
• The engine is running.

• Before the ECM will report a P0128 fault, the P0117 test must pass.
• DTCs P0101, P0102, P0103, P0112, P0113, P0118, P0722, or P0723 are not set.
• Engine speed is above 960 rpm.
• ECT temperature below 71°C (160°F) at startup.
• The calculated outside air temperature is above -11°C (-12°F) and below 45°C (113°F).
• The vehicle speed is greater than 15 km/h (9 mph).
• The total air consumption of the engine was more than 2000 g.
• DTC P0128 will set continuously if the above conditions have been met for approximately 15 minutes.

• The ECM detects that the actual coolant temperature is 10°C (18°F) less than the calculated temperature.
• This condition persists for more than 4 seconds.

1. Check the engine coolant level.
• If the engine coolant level is not as specified, proceed to Section 1D1, "Engine Cooling".
2. Check that the engine coolant temperature is equal to normal operating temperature.
• If the coolant temperature is below normal operating temperature, proceed to Section 1D1, Engine Cooling.
3. Ensure the conditions required to run the diagnostic. You may also ensure the conditions you observed from the Freeze Frame/Failure Records data. DTCs P0125 or P0128 should not set.
4. If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.

1. Turn off ignition, disconnect harness connector from ECT sensor.
2. Turn ignition off, check for less than 5 ohms of resistance between the low reference circuit and ground.
• If more than 5 ohms, then check the low reference signal circuit for a short circuit to a live wire or for open / high resistance. If no fault is detected during circuit testing, then replace the ECM controller.
3. Turn on the ignition, use a scan tool to check if the ECT sensor parameter is -40°C (-40°F).
• If greater than -40°C (-40°F), test the signal circuit for a short to ground. If no fault is found when testing the circuit/connections, replace the ECM.

Important: If the ECT sensor signal circuit is shorted to a live wire, the ECT sensor may be damaged.

4. Connect a jumper wire with a 3 A fuse between the signal circuit and the low reference circuit. Make sure that the parameter "ECT sensor" has a value greater than 128°C (262°F).
• If it is less than 128°C (262°F), then check the signal circuit for a short circuit to a live wire or for open / high resistance. If no fault is detected during circuit / connection testing, replace the ECM controller.
5. If all circuits are good, check or replace the ECT sensor.

1. Turn off ignition, disconnect harness connector from ECT sensor.

Important: Important: You can use a thermometer to check the sensor outside the vehicle.

2. Check the ECT sensor by changing its temperature and simultaneously measuring the electrical resistance of the sensor. Compare the results with the values given in the table Resistance vs. Temperature. Intake Air Temperature Sensor (IAT). The measured resistances should not differ from the required values by more than 5 percent.
• If the resistances differ by more than 5 percent, the ECT sensor must be replaced.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
HO2S Signal Bank 1 Sensor 1	P0131	P0130, P0134	P0132	P0130, P0133
HO2S Signal Bank 2 Sensor 1	P0137	P0136, P0140	P0138	P0136, P0139
HO2S Signal Bank 2 Sensor 1	P0151	P0150, P0154	P0152	P0150, P0153
HO2S Signal Bank 2 Sensor 2	P0157	P0156, P0160	P0158	P0156, P0159
Low reference voltage	-	P0130, P0136, P0150, P0156	P0134, P0140, P0154, P0160	-

• Ignition voltage within 10-16 V.
• The engine is running.

1. Engine idling, determine voltage for the corresponding HO2S sensor. The value should fluctuate up and down in the range of 350-550 mV.
2. If the vehicle passes the Circuit/System Check test, the vehicle should be operated within the conditions that set the DTC. You may also operate the vehicle within the conditions that are recorded in the Freeze Frame/Failure Records data.

1. Turn ignition off, disconnect harness connector from appropriate HO2S sensor.
2. Turn on the ignition, check that the HO2S parameter is in the range of 350-500 mV.
• If less than 350 mV, check the signal circuit for a short to ground. If the circuits and connectors are OK, replace the ECM.
• If voltage is greater than 500 mV, test signal circuit for short to supply voltage. If circuit/connections test normal, replace ECM.
3. Turn ignition off, test for 5 ohms or less between the HO2S low reference circuit and ground.
• If resistance is greater than 5 ohms, test the low reference circuit for an open/high resistance. If circuit/connections test normal, replace the ECM.
4. Connect a 3 Amp fused jumper wire between the signal circuit and the HO2S low reference circuit and test if the HO2S parameter is less than 60 mV.
• If greater than 60 mV, test signal circuit for open/high resistance. If circuit/connections test normal, replace ECM.
5. If no fault is found when testing all circuits/connections, replace the HO2S sensor.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
HO2S Signal Bank 1 Sensor 1	P0131	P0130, P0134	P0132	P0130, P0133
HO2S Signal Bank 2 Sensor 1	P0137	P0136, P0140	P0138	P0136, P0139
HO2S Signal Bank 2 Sensor 1	P0151	P0150, P0154	P0152	P0150, P0153
HO2S Signal Bank 2 Sensor 2	P0157	P0156, P0160	P0158	P0156, P0159
Low reference voltage	-	P0130, P0136, P0150, P0156	P0134, P0140, P0154, P0160	-

• Ignition voltage within 10-16 V.
• The engine is running.

1. Engine idling, determine voltage for HO2S sensor Voltage should fluctuate up and down in the range of 350-550 mV.
2. If the vehicle passes the Circuit/System Check test, the vehicle should be operated within the conditions that set the DTC. You may also operate the vehicle within the conditions that are recorded in the Freeze Frame/Failure Records data.

1. Turn ignition off, disconnect harness connector from appropriate HO2S sensor.
2. Turn on ignition, check that HO2S voltage is in the range of 350-500 mV.
• If less than 350 mV, check the signal circuit for a short to ground. If the circuits and connectors are OK, replace the ECM.
• If voltage is greater than 500 mV, test signal circuit for short to supply voltage. If circuit/connections test normal, replace ECM.
3. Turn ignition off, test for 5 ohms or less between the low reference circuit and ground.
• If resistance is greater than 5 ohms, test the low reference circuit for an open/high resistance. If circuit/connections test normal, replace the ECM.
4. Connect a 3-amp fused jumper wire between the signal circuit and the low reference circuit of the sensor and test if the HO2S sensor voltage is less than 60 mV.
• If greater than 60 mV, test the HO2S signal circuit for an open/high resistance. If no fault is found when testing the circuit/connections, replace the ECM.
5. Check that the following conditions are not met:
• Lean mixture on fuel injectors
• Low pressure in the fuel system
• The fuel is contaminated
• Exhaust leak near HO2S sensor
• Engine vacuum leak
• If any of the above faults are detected, they should be corrected.
6. If no fault is found when testing all circuits/connections, replace the HO2S sensor.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
HO2S Signal Bank 1 Sensor 1	P0131	P0130, P0134	P0132	P0130, P0133
HO2S Signal Bank 2 Sensor 1	P0137	P0136, P0140	P0138	P0136, P0139
HO2S Signal Bank 2 Sensor 1	P0151	P0150, P0154	P0152	P0150, P0153
HO2S Signal Bank 2 Sensor 2	P0157	P0156, P0160	P0158	P0156, P0159
Low reference voltage	-	P0130, P0136, P0150, P0156	P0134, P0140, P0154, P0160	-

• Ignition voltage within 10-16 V.
• The engine is running.

1. Engine idling, determine voltage for HO2S sensor Voltage should fluctuate up and down in the range of 350-550 mV.
2. If the vehicle passes the Circuit/System Check test, the vehicle should be operated within the conditions that set the DTC. You may also operate the vehicle within the conditions that are recorded in the Freeze Frame/Failure Records data.

1. Turn ignition off, disconnect harness connector from appropriate HO2S sensor.
2. Turn on ignition, check that HO2S voltage is in the range of 350-500 mV.
• If less than 350 mV, check the signal circuit for a short to ground. If the circuits and connectors are OK, replace the ECM.
• If voltage is greater than 500 mV, test signal circuit for short to supply voltage. If circuit/connections test normal, replace ECM.
3. Turn ignition off, test for 5 ohms or less between the low reference circuit and ground.
• If resistance is greater than 5 ohms, test the low reference circuit for an open/high resistance. If circuit/connections test normal, replace the ECM.
4. Connect a 3-amp fused jumper wire between the signal circuit and the low reference circuit of the sensor and test if the HO2S sensor voltage is less than 60 mV.
• If greater than 60 mV, test signal circuit for open/high resistance. If circuit/connections test normal, replace ECM.
5. Check that the following conditions are not met:
• Lean mixture at the fuel injector
• High pressure in the fuel system
• The fuel is contaminated
• Obstructions in the exhaust system
• If any of the above faults are detected, they should be corrected.
6. If no fault is found when testing all circuits/connections, replace the HO2S sensor.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
HO2S Signal Bank 1 Sensor 1	P0131	P0130, P0134	P0132	P0130, P0133
HO2S Signal Bank 2 Sensor 1	P0137	P0136, P0140	P0138	P0136, P0139
HO2S Signal Bank 2 Sensor 1	P0151	P0150, P0154	P0152	P0150, P0153
HO2S Signal Bank 2 Sensor 2	P0157	P0156, P0160	P0158	P0156, P0159
Low reference voltage	-	P0130, P0136, P0150, P0156	P0134, P0140, P0154, P0160	-

• Ignition voltage within 10-16 V.
• The engine is running.

1. Verify that no other diagnostic trouble codes are set.
• If any of the codes are set, you need to refer to the information for that code.
2. Engine idling, determine voltage for HO2S sensor Voltage should fluctuate above and below 350-550 mV range.
3. Ensure that the vehicle operates as required to perform the diagnostic. DTCs P0133 and P0153 should not set.
4. If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.

1. Check for the following faults:
• Lean mixture on fuel injectors
• Water ingress into the HO2S harness connector
• Damage to the HO2S wiring harness
• Incorrect RTV sealing
• Low or high pressure in the fuel system
• The fuel is contaminated
• Fuel saturation of the SUPB adsorber
• Exhaust gas leak near the HO2S oxygen sensor
• Engine vacuum leak
• Engine oil consumption
• Engine coolant consumption
• If any of the above faults are detected, they should be corrected.
2. If all these faults are absent, then replace the corresponding HO2S.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
Ignition voltage 1	P0135, P0141	P0135, P0141	-	-
HO2S Sensor Heater Control Circuit 1	P0135	P0135	P0135	-
HO2S Sensor Heater Control Circuit 2	P0141	P0141	P0141	-

• Ignition voltage within 10-16 V.
• The engine is running.

Important: It may take up to 8 minutes for the diagnostic trouble code to set.

1. Warm up the engine to normal operating temperature, raise the engine speed above 1200 RPM for 30 seconds, then let the engine idle. DTCs P0135, P0141, P0155, or P0161 should not set.
2. If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.

1. Turn ignition off, disconnect harness connector from appropriate HO2S.
2. Turn on ignition, check under load for battery voltage in the HO2S heater ignition voltage circuit.
• If the voltage is less than B+, eliminate the short to ground or open/high resistance in the HO2S heater ignition voltage circuit.
3. Turn off ignition, connect test lamp between HO2S heater control circuit terminal and B+.
• If the test lamp illuminates, test the HO2S heater control circuit for a short to ground. If the circuit/connections test normal, replace the ECM.
4. Turn ignition on, test for less than 0.3 V between the HO2S heater control circuit at the test lamp connection point and ground.
• If the voltage is greater than 0.3 V, check the control circuit of the HO2S heater for a short circuit to a live wire or open / high resistance. If no fault is detected during circuit / connection testing, replace the ECM controller.
5. If no fault is found when testing all circuits/connections, test or replace the HO2S sensor.

1. Turn ignition off, disconnect harness connector from appropriate HO2S.
2. Check the resistance of the oxygen sensor heater, which should be 3-35 Ohms.
• If the resistance is not within the specified range, replace the HO2S.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
HO2S Signal Bank 1 Sensor 1	P0131	P0130	P0132	P0130, P0133, P0134
HO2S Signal Bank 2 Sensor 1	P0137	P0136	P0138	P0136, P0139, P0140
HO2S Signal Bank 2 Sensor 1	P0151	P0150	P0152	P0150, P0153, P0154
HO2S Signal Bank 2 Sensor 2	P0157	P0156	P0158	P0156, P0159, P0160
Low reference voltage	-	P0130, P0136, P0150, P0156	P0132, P0138, P0152, P0158	-

• Ignition voltage within 10-16 V.
• The engine is running.

1. With the engine running, measure the heated oxygen sensor (HO2S) voltage. The value should fluctuate up and down in the range of 350-550 mV.
2. If the vehicle passes the Circuit/System Check test, the vehicle should be operated within the conditions that set the DTC. You may also operate the vehicle within the conditions that are recorded in the Freeze Frame/Failure Records data.

1. Turn ignition off, disconnect harness connector from appropriate HO2S.
2. Turn on the ignition, check that the HO2S parameter is in the range of 350-500 mV.
• If less than 350 mV, check the HO2S signal circuit for a short to ground. If the circuits and connectors are OK, replace the ECM.
• If the voltage is higher than 500 mV, check the signal circuit of the HO2S oxygen sensor for a short circuit to the supply voltage. If no fault is detected during circuit / connection testing, replace the ECM controller.
3. Turn ignition off, check resistance between HO2S low reference circuit and ground, it should be less than 5 ohms.
• If greater than 5 ohms, check the low reference circuit of the HO2S sensor for open / high resistance. If no fault is detected during circuit / connection testing, replace the ECM controller.
4. Connect a 3 Amp fused jumper wire between the signal circuit and the HO2S low reference circuit and test if the HO2S parameter is less than 60 mV.
• If greater than 60 mV, test the HO2S signal circuit for an open/high resistance. If no fault is found when testing the circuit/connections, replace the ECM.
5. Check that the following conditions are not met:
• Lean mixture on fuel injectors
• Low pressure in the fuel system
• The fuel is contaminated
• Exhaust leak near HO2S sensor
• Engine vacuum leak
• If any of the above faults are detected, they should be corrected.
6. If no fault is found when testing all circuits/connections, replace the HO2S sensor.

• The engine ran for more than 10 seconds.
• This fault code is issued continuously when the conditions for issuing are met.

1. Turn on the ignition, engine off.
2. Disconnect the EOT sensor wiring harness connector.
3. Measure the voltage at the EOT sensor harness connector, which should be in the range of 4.9-5.2 V.
• If voltage is below 4.9 V, test the EOT sensor circuit for a short to ground or an open/high resistance.
• If voltage is greater than 5.2 V, check EOT sensor circuit for short to supply voltage.
• If the EOT sensor circuit is normal and the voltage is outside the specified range, replace the ECM.
4. Connect a 3A fused jumper wire between the EOT sensor signal circuit and the low reference circuit.
• Monitor the sensor parameters by connecting and disconnecting the jumper between the EOT sensor signal circuit and the low reference circuit.
• The EOT sensor value should toggle between the upper and lower limits.
• If the EOT signal does not switch between the high and low limits, replace the ECM.
• If the EOT signal switches between the upper and lower limits, replace the EOT sensor.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
Ignition voltage 1	P0201, P0202, P0203, P0204, P0205, P0206	P0201, P0202, P0203, P0204, P0205, P0206	-	-
Injector 1 control circuit	P0261	P0201	P0262	-
Injector 2 control circuit	P0264	P0204	P0265	-
Injector 3 control circuit	P0267	P0203	P0268	-
Injector 4 control circuit	P0270	P0204	P0271	-
Injector 5 control circuit	P0273	P0205	P0274	-
Injector 6 control circuit	P0276	P0206	P0277	-

• Engine speed is above 80 rpm.
• Ignition voltage 1 in the range of 10-18 V.
• Diagnostic tests are performed continuously when the above conditions are met.

1. Using a scan tool, obtain the current misfire counter data. The current misfire counter data should not increase.
2. With the engine running, observe the trouble code information with a scan tool. Trouble codes P0201, P0202, P0203, P0204, P0205, P0206, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, and P0277 should not be set.

Important: Disconnecting the multi-pin harness connector will cause diagnostic trouble codes P0201-P0206 to appear (fuel injector circuit open).

1. Turn off the ignition, disconnect the multi-pin connector of the fuel injector harness.
2. Turn on the ignition, check the voltage between the ignition voltage circuit 1 and the positive terminal of the battery, which should be less than 0.1 V.

Important: The ignition circuit supplies voltage to other components. It is necessary to ensure that all circuits are checked for shorts to ground and that all components that are part of the ignition circuit are checked for shorts.

• If voltage is above 0.1 V, repair short to ground in fuel injector ignition voltage circuit 1 between fuel injector and fuse. Or, check for open/high resistance between multi-pin connector and B+. Replace fuse if necessary.
3. Connect a test lamp between the multi-pin connector terminal of the control circuit harness of the corresponding injector on the ECM side and B+.
4. Turn the engine over with the starter, the indicator lamp should flash.
• If the indicator lamp is constantly on, check the control circuit for a short to ground. If the circuit/connectors are OK, replace the ECM.
• If the test lamp does not illuminate at all, test the control circuit for a short to voltage or an open/high resistance. If the circuit/connections test normal, replace the ECM.
5. Turn on the ignition, measure the voltage between the fuel injector control circuit (controller side of the multi-pin connector) and "mass", which should be equal to 2.6 - 4.6 V.
• If the voltage is not within the specified range and no fault is found when testing the circuit/connections, replace the ECM.
6. Remove the upper intake manifold.
7. Disconnect the fuel injector connectors.
8. Check the resistance between the ignition 1 voltage circuit(s) and the appropriate injector control circuit, at the injector side of the harness multi-pin connector. The DMM should indicate overload.
• If the resistance is less, eliminate the short circuit between the ignition voltage circuit 1 and the control circuit of the corresponding fuel injector.
9. Using a digital multimeter, measure the resistance of the appropriate ignition voltage circuit 1, between the injector connector(s) and the multi-pin connector, which should be less than 1 ohm.
• If the resistance is greater than 1 ohm, repair the open/high resistance in the ignition voltage circuit 1.
10. Measure the resistance of the control circuit that may be faulty; the resistance between the injector connector and the multi-pin connector should be less than 1 Ohm.
• If the resistance is greater than 1 ohm, then eliminate the open/high resistance in the fuel injector control circuit.
11. Measure the resistance between the control circuit of the appropriate fuel injector and ground. The digital multimeter should indicate an overload.
• If the resistance is less, then eliminate the short circuit to ground in the fuel injector control circuit.
12. Measure the resistance between the fuel injector control circuit suspected of having a fault and all other fuel injector control circuits. The DMM should indicate an overload.
• If the resistance for any pair of circuits is less, then eliminate the short circuit of the wires of these circuits.
13. If no fault is found when all circuits/connections are tested, check or replace the fuel injector(s).

1. Measure the resistance between the fuel injector contacts, which should be 12-16 Ohms.
• If the resistance is not within the specified range, replace the fuel injector.

• The car is equipped with a manual transmission.
• The engine is running.
• Ignition voltage within 10-16 V.

• An engine overspeed condition can only occur if a low gear is engaged on a manual transmission while the vehicle is traveling at high road speed. This fault code cannot be set by randomly overspeeding the engine.

1. Start the engine and operate the vehicle under normal driving conditions. Trouble code P0219 should not set.

1. If no other DTCs are set. Clear this DTC using a scan tool. Operate the vehicle within the conditions for setting this DTC.
• If this DTC occurs again, replace the ECM.

• Diagnostic trouble codes P0121, P0122, P0123, P0221, P0222, P0223, P0335, P0336, or P0338 are not set.
• Engine speed is in the range of 400 - 7000 rpm and is constant.
• The engine running time exceeds 45 seconds.
• The received torque signal at idle speed exceeds 10 percent.
• The received torque signal is in the range of 9-30 percent when the gear is engaged.
• Intake air temperature (IAT) is above -30°C (-22°F).
• The air conditioning compressor clutch does not change state.
• Torque control is not available.
• Anti-lock brake system/traction control system (ABS/TCS) does not function.
• The ECM is not receiving a rough road signal.
• Fuel level is over 12 percent.
• The ECM is not in normal fuel cut or deceleration fuel cut mode.
• The throttle angle does not change.
• DTC P0300 sets continuously when the above conditions are met for at least 1000 engine revolutions.

• The tire or wheel is not round or out of balance
• Variable thickness brake rotors
• Unbalanced propeller shaft
• Certain conditions on a bad road
• Damage to drive belt or accessory

1. The engine is idling at normal operating temperature.
• If abnormal engine noise is detected, please refer to the section Part 1C2, "Mechanical part of the HFV6 3.2 L engine."
2. Verify that DTCs P0011, P0014, P0021, P0024, P0201–P0206, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, P0277, P0335, P0336, P0338, P0351–P0356, P2088, P2090, P2092, P2094, P2300, P2301, P2303, P2304, P2306, P2307, P2309, P2310, P2312, P2313, P2315, or P2316 not installed.
• If any of these codes are set, you should refer to the information for that code.
3. Using a scanning device, obtain data on current misfires in cylinders 1-6. The data on the current misfire counters should not increase.
4. Engine idling, perform a cylinder power balance test with a scan tool to identify the cylinder that is misfiring. The engine speed should change as each injector is turned off.

1. Check that the following conditions are not met:
• Cracks, kinks or loose connections in vacuum hoses
• Engine vacuum leak
• Crankcase ventilation system for vacuum leaks
• Low or high pressure in the fuel system
• The fuel is contaminated
• Obstructions in the exhaust system
• If any of the above faults are detected, they should be corrected.
2. Turn off the ignition, remove the ignition coil of the cylinder that is misfiring, but do not disconnect the electrical connector.
3. Inspect the ignition coil boot for the following faults:
• Holes
• Tears
• Carbon tracks
• Oiling
• Water ingress
• If any of the above faults are detected, they should be corrected.
4. Remove the fuel pump fuse from the fuse box.
5. Install a spark plug tester on the spark plug.

Important: Failures in spark formation or a weak spark are considered as no spark.

6. Start the engine, observing the tester readings. The spark tester should produce a spark
• If there is no spark, check the spark plug wire resistance, which should be 1000 ohms per 31 cm (per 1 foot). Replace the wire if the resistance is greater.
7. Turn off ignition, remove spark plug from cylinder where misfiring occurs. Check spark plug to make sure there are no following faults:
• Contamination with fuel, coolant or oil
• Cracks, wear, incorrect clearance
• If any of these faults are detected, replace the spark plug.
8. Move the spark plug that is suspected of being faulty to another cylinder that is working properly.
9. With the engine idling, use a scan tool to obtain current misfire data. Misfires should not occur in the cylinder to which this spark plug has been moved.
• If misfires still occur, replace this spark plug.
10. If all these faults are absent, then check the following:
• Lean or rich mixture at the fuel injector
• Mechanical defects of the engine

1. If the customer reported a flashing Malfunction Indicator Lamp (MIL), refer to the Diagnostic Trouble Codes section.
2. Use a scan tool to clear DTC codes.
3. Turn off the ignition for 30 seconds.
4. Start the engine.
5. Condition the vehicle for running the DTC. You can also condition the vehicle to run the conditions that were observed based on the recorded malfunction data.
• If the diagnostic code was set again with this ignition, the misfire still continues.

• Before the ECM will report DTCs P0327, P0328, P0332, or P0333, DTCs P0324, P0335, P0336, and P0338 must pass.
• DTCs P0341, P0342, P0343, P0346, P0347, P0348, P0366, P0367, P0368, P0391, P0392, and P0393 are not set.
• The ECM controls the ignition.
• Engine coolant temperature (ECT) is above 60°C (140°F).
• Engine speed is stable and above 2000 rpm.
• Volumetric efficiency is stable.
• DTCs P0327, P0328, P0332, and P0333 run continuously when the above conditions are met for approximately 20 seconds.

• Check for physical damage to the knock sensor. A sensor that has been dropped or damaged may cause a DTC to set.
• Check that the KS sensor is installed correctly. A sensor that is loose or overtightened may cause a DTC to be set. There should be no traces of thread sealant on the KS sensor. The sensor mounting surface should be free of burrs, casting flash, and foreign material.
• The sensor must not come into contact with hoses, brackets or engine wiring.
• Normally, the signal voltage of a disconnected sensor is 0.25 V.

1. Start the engine. Obtain trouble code information using a scan tool. DTCs P0324, P0327, P0328, P0332, or P0333 should not be set.
2. If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.

1. Turn off the ignition, disconnect the harness connector of the corresponding KS sensor.
2. Turn on the ignition, connect a test lamp between the sensor signal circuit and the negative terminal of the battery.
• If the test lamp is illuminated, check the signal circuit for a short to a live wire. If no fault is found when testing the circuits/connections, replace the ECM.
3. Turn on the ignition, connect a test lamp between the sensor signal circuit and the positive terminal of the battery.
• If the test lamp is on, check the signal circuit for a short to ground. If no fault is found when testing the circuits/connections, replace the ECM.
4. Turn off the ignition, measure the resistance between the low reference signal circuit of the KS sensor and ground, which should be less than 5 Ohms.
• If resistance exceeds the specified value, test the low reference circuit for an open/high resistance. If circuits/connections test normal, replace the ECM.
5. If no fault is found when testing all circuits/connections, replace the KS sensor.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
CKP sensor signal	P0335	P0335	P0335	P0336
Low reference voltage	-	P0335	P0335, P0338	P0336
Shielded "ground" wire	-	-	-	P0336

• The engine is turned over by the starter or is running.
• The ECM has detected more than 12 camshaft revolutions.
• Diagnostic tests are performed continuously when the above conditions are met.

• Physical damage to the CKP sensor or pulse sensor.
• Excessive play or looseness of the CKP sensor or pulse sensor.
• Incorrect installation of the CKP sensor or pulse sensor.
• Foreign material appears between the CKP sensor and the pulse sensor.
• The gap between the CKP sensor and the pulse sensor is too large.
• The ECM uses the camshaft position sensors to determine engine speed and crankshaft position in the event of a faulty crankshaft sensor.
• The engine will run with a faulty CKP sensor only if the ECM has stored previously determined initial camshaft positions in memory. If the crankshaft position sensor is faulty, the engine will go into emergency mode after a difficult start. The ECM will then calculate the engine speed based on signals from one of the camshaft position sensors. The emergency mode may also set the following additional diagnostic codes, which should be ignored:
• DTC P0324 Knock Sensor Module Performance.
• DTC P1011 Intake camshaft timing control, neutral position, cylinder row 1
• The CKP sensor diagnostic trouble code may be set due to an intermittent fault in the camshaft position (CMP) sensor circuits. If this fault is suspected, the CMP sensor, harness connections, and associated wiring should be inspected.

1. Turn on the ignition, check the DTC data with the scanning device. Try to start the engine, use the scanning device to get information about diagnostic trouble codes. The codes P0335, P0336, and P0338 should not be set.
2. Wiggle the CKP sensor harnesses/connections while observing the engine, which should not run rough, stall, or change speed.
3. If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.

Important: If the CKP sensor terminal is damaged in any way, replace the sensor.

1. Turn off ignition, disconnect harness connector from crankshaft position (CKP) sensor.
2. Turn on the ignition, check for 2.0-3.0 V in the signal circuit and in the low reference circuit of the CKP sensor.
• If less than 2.0 V, test the appropriate circuit for a short to ground or an open/high resistance. If no fault is found when testing the circuits/connections, replace the ECM.
• If greater than 3.0 V, test the appropriate circuit for a short to voltage. If no fault is found when testing the circuits/connections, replace the ECM.
3. Turn off the ignition, measure the resistance between the grounded screen circuit of the CKP sensor connector and the ground, which should be equal to 5 Ohms.
• If the resistance is greater than 5 ohms, correct the open/high resistance in the CKP sensor shield circuit.
4. Disconnect the ECM connectors and measure the resistance between the following circuits:
• CKP signal circuit and CKP low reference circuit.
• CKP signal circuit and grounded shield circuit.
• CKP low reference circuit and grounded shield circuit.
For all circuits the digital multimeter should show overload.
• If there is conductivity between any of these circuits, then eliminate the short circuit of the wires of these circuits.
5. If no fault is found when testing all circuits/connections, check or replace the CKP sensor.

1. Turn off ignition, disconnect harness connector from crankshaft position (CKP) sensor.

Important: If the CKP sensor terminal is damaged in any way, replace the sensor.

2. Connect a digital multimeter between the signal circuit and the low reference circuit of the CKP sensor.
3. Measure the resistance between the signal circuit and the low reference circuit, which should be 700-1200 ohms.
• If the resistance is not within the specified range, replace the CKP sensor.
4. Switch the digital multimeter to measure AC voltage.
5. Measure the resistance between the signal circuit and the low reference circuit, which should be 700-1200 ohms.
• If less than 1.4 VAC, replace the CKP sensor.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
CMP Sensor 5V Reference Voltage	P0343, P0348, P0368, P0393	P0343, P0348, P0368, P0393	-	P0341, P0346, P0366, P0391
CMP Sensor Signal, Intake, Bank 1	P0342	P0343	P0343	P0341
CMP Sensor Signal, Intake, Bank 2	P0347	P0348	P0348	P0346
CMP Sensor Signal, Exhaust, Bank 1	P0367	P0368	P0368	P0366
CMP Sensor Signal, Exhaust, Bank 2	P0392	P0393	P0393	P0391
Low reference voltage	-	P0343, P0348, P0368, P0393	-	P0341, P0346, P0366, P0391

• The engine runs for more than 1 second.
• Diagnostic tests are performed continuously when the above conditions are met.

• Physical damage to the CMP sensor or pulse sensor.
• Excessive play or looseness in the CMP sensor or chopper gear.
• Incorrect installation of CMP sensor or breaker gear.
• Foreign material appears between the CMP sensor and the pulse sensor.
• Inadmissible gap between CMP sensor and chopper gear.

1. Turn off the ignition, remove the fuse/relay of the ECM controller, through which the voltage "B+" is supplied to the controller contact.
2. Disconnect the harness connector from the appropriate CMP sensor.

Note: DO NOT use a test lamp to check for continuity. Damage to this control unit may result in increased current.

Important: The controller or sensor may be damaged if the circuit is shorted to B+.

3. Test for 5 ohms or less resistance between the low reference circuit and a good ground.
• If resistance is greater than 5 ohms, test the low reference circuit for an open/high resistance, or a short to a live wire. If no fault is found when testing the circuit/connections, replace the ECM.
4. Install the ECM fuse that supplies "B+" voltage to the ECM.
5. Turn on the ignition, measure the voltage between the 5V reference circuit of the CMP sensor and a reliable ground, which should be 4.8 - 5.2 V.
• If less than 4.8 V, test the 5 V reference circuit for a short to ground or an open/high resistance. If no fault is found when testing the circuits/connections, replace the ECM.
• If greater than 5.2 V, test the 5 V reference circuit for a short to voltage. If no fault is found when testing the circuits/connections, replace the ECM.
6. Using a digital multimeter, measure the voltage between the CMP sensor signal circuit and a reliable ground, which should be 4.8 - 5.2 V.
• If the voltage is greater than 5.2 V, then check the signal circuit of the CMP sensor for a short circuit to the live wire. If no fault is detected during circuit / connection testing, replace the ECM controller.
• If the voltage is less than 4.8 V, check the signal circuit of the CMP sensor for a ground fault or open / high resistance. If no fault is detected during circuit / connection testing, replace the ECM controller.
7. If no fault is found when testing all circuits/connections, replace the CMP sensor.

• The engine is running.
• Ignition voltage 1 is within 10.5 - 18 volts.
• Engine speed is in the range of 1400 - 5000 rpm.
• Diagnostics are performed continuously as soon as the above conditions are met for more than 1 second.

1. Turn on the ignition, disconnect the harness connector from the corresponding ignition coil.
2. Turn on the ignition, make sure that the test lamp connected between the ignition circuit contact and a reliable ground does not light.
• If the test lamp does not light, check the ignition circuit for a short to ground or an open/high resistance. If no fault is found when testing the circuit and there is an open in the ignition circuit fuse, check the circuit contact for a short to ground.
3. This test requires you to switch your digital multimeter to measure AC frequency.
4. Crank or start the engine, measure the frequency between the appropriate ignition control circuit and a reliable ground; the frequency must be greater than 3 Hz.
• If the frequency is less than 3 Hz, test the ignition control circuit for a short to hot wire, a short to ground, and an open/high resistance. If no fault is found when testing the circuit/connection, replace the ECM.
5. Measure the resistance between both ground circuits of the ignition coil connector and the ECM housing, which should be no more than 5 ohms.
• If resistance is greater than 5 ohms, test ground circuits for open or high resistance. If circuit/connections test normal, replace ECM.
6. If no fault is found when testing all circuits/connections, replace the ignition coil.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
Ignition voltage 1	P0261, P0264, P0267, P0270, P0273, P0276, P0300-P0306	P0300-P0306	-	P0300-P0306
Ignition Coil 1 Control Circuit	P2300	P0351	P2301	P0300, P0301
Ignition Coil 2 Control Circuit	P2303	P0352	P2304	P0300, P0302
Ignition Coil Control Circuit 3	P2306	P0353	P2307	P0300, P0303
Ignition Coil Control Circuit 4	P2309	P0354	P2310	P0300, P0304
Ignition Coil Control Circuit 5	P2312	P0355	P2313	P0300, P0305
Ignition Coil Control Circuit 6	P2315	P0356	P2316	P0300, P0306

• The engine is running.
• Ignition voltage 1 is within 10.5 - 18 volts.
• Engine speed is in the range of 1400 - 5000 rpm.
• Diagnostics are performed continuously as soon as the above conditions are met for more than 1 second.

1. Turn on the ignition, disconnect the harness connector from the corresponding ignition coil.
2. Turn on the ignition, make sure that the test lamp connected between the ignition circuit contact and ground does not light.
• If the test lamp does not light, check the ignition circuit for a short to ground or an open/high resistance. If no fault is found when testing the circuit and there is an open in the ignition circuit fuse, check the circuit contact for a short to ground.
3. This test requires you to switch your digital multimeter to measure AC frequency.
4. Crank the starter or start the engine, measure the frequency between the corresponding ignition control circuit and the "ground"; the frequency must be greater than 3 Hz.
• If the frequency is less than 3 Hz, test the ignition control circuit for a short to hot wire, a short to ground, and an open/high resistance. If no fault is found when testing the circuit/connection, replace the ECM.
5. Measure the resistance between both ground circuits of the ignition coil connector and the ECM housing, which should be no more than 5 ohms.
• If resistance exceeds 5 ohms, check for open or high resistance in ground circuits. If no fault is found when testing circuit/connections, replace ECM.
6. If no fault is found when testing all circuits/connections, replace the ignition coil.

• The amount of oxygen stored in the catalyst exceeds a specified threshold, which is determined by the signal from the diagnostic oxygen sensor.
• The diagnostic oxygen sensor shows that the catalyst is fully saturated with oxygen, which is determined by the signal from the diagnostic sensor.

• Before the ECM can set DTCs P0420 or P0430, DTCs P0030, P0031, P0032, P0036, P0037, P0038, P0050, P0051, P0052, P0053, P0056, P0057, P0058, P0059, P0101, P0102, P0103, P0121, P0122, P0123, P0130, P0131, P0132, P0133, P0135, P0137, P0138, P0140, P0141, P0150, P0151, P0152, P0153, P0155, P0157, P0158, P0160, P0161, P0221, P0222, P0223, P0335, P0336, P0338, P167A, P167B, P2096, P2097, P2098, P2099, P2195, P2196, P2197, P2198, P2232, P2235, P2237, P2240, P2243, P2247, P2251, P2254, P2270, P2271, P2272, P2273, P2297, P2298, P2626, and P2629.
• DTCs P0010, P0011, P0013, P0014, P0020, P0021, P0023, P0024, P0030, P0031, P0032, P0036, P0037, P0038, P0050, P0051, P0052, P0053, P0056, P0057, P0058, P0059, P0101, P0102, P0103, P0116, P0117, P0118, P0119, P0121, P0122, P0123, P0125, P0130, P0131, P0132, P0133, P0135, P0137, P0138, P0140, P0141, P0150, P0151, P0152, P0153, P0155, P0157, P0158, P0160, P0161, P0221, P0222, P0223, P0300, P0301–P0306, P0443, P0458, P0459, P0496, P167A, P167B, P2088, P2089, P2090, P2091, P2092, P2093, P2094, P2095, P2096, P2097, P2098, P2099, P2100, P2101, P2107, P2119, P2122, P2123, P2127, P2128, P2138, P2176, P2177, P2178, P2179, P2180, P2187, P2188, P2189, P2190, P2195, P2196, P2197, P2198, P2232, P2235, P2237, P2240, P2243, P2247, P2251, P2254, P2270, P2271, P2272, P2273, P2297, P2298, P2626 and P2629
• Engine speed is in the range of 1040 - 3000 rpm.
• The air flow rate entering the engine is in the range of 7 - 16 g/s and does not change by more than 3 g/s.
• The intake air temperature (IAT) entering the engine at start-up is greater than -30°C (-22°F).
• The engine has been running for more than 7 minutes.
• The engine operates in closed loop mode.
• The calculated catalytic converter temperature is in the range of 500-750°C (932-1382°F) and is constant.
• The above conditions exist for approximately 17 minutes.
• Diagnostic tests for DTCs P0420 and P0430 run once per drive cycle. The ECM will attempt to run this diagnostic up to 3 times per drive cycle.

• Misfires
• High oil or coolant consumption
• Reducing ignition timing
• Weak spark
• Lean air-fuel mixture
• Rich air-fuel mixture
• Damaged oxygen sensor or wiring harness

1. Make sure there are no diagnostic trouble codes set related to the oxygen sensors or misfires.
• If oxygen sensor or misfire related diagnostic trouble codes are set, refer to the appropriate code information to determine the cause of the fault before performing this diagnostic procedure.
2. Check whether the corresponding catalytic converter has the following faults:
• Dents
• Very strong color change caused by excessively high temperatures.
• Road damage
• Rattling of internal components caused by damage to the catalyst substrate.
• Internal obstructions to gas movement
• If any of the faults are detected, the corresponding catalytic converter should be replaced.
3. Check the exhaust system for the following faults:
• Leaks
• Physical damage
• Poorly secured or missing structural elements
• Poorly tightened oxygen sensor
• If any fault is detected, repair the exhaust system.
4. Check if the HO2S2 oxygen sensor has the following faults:
• Grounding the wiring harness
• Damage
• If any of the faults are detected, the corresponding HO2S2 oxygen sensor should be replaced.
5. If no physical faults are found and after running the engine at 1500 rpm for 1 minute and then returning to a stable idle, the HO2S 2 signal value is the same as HO2S 1, then the catalytic converter should be replaced.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
Ignition voltage 1	P0458	P0443	-	-
Evaporative emission control system canister purge valve control circuit	P0458	P0443	P0459	-

• The ignition is on or the engine is running.
• Engine speed is more than 80 rpm
• Ignition voltage 1 is within 10.5 - 18 volts.
• The ECM controller sends an on and off command to the purge valve of the SUPB adsorber at least once per ignition cycle.
• Diagnostic tests are performed continuously when the above conditions are met.

1. Turn on the ignition, use a scanning device to send the commands "on" and "off" to the EGR purge valve. A click should be heard.
2. If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.

1. Turn off the ignition, disconnect the harness connector of the ESP purge valve at the purge valve.
2. Turn on the ignition, make sure that the test lamp connected between the ignition voltage circuit 1 and ground does not light.
• If the test lamp does not illuminate, check the ignition 1 voltage circuit for a short to ground or an open/high resistance. If no fault is found in the circuit and the ignition 1 voltage circuit fuse is open, check all components connected to the ignition 1 voltage circuit and replace as necessary.
3. Connect a test lamp between the control circuit terminal and the ignition voltage circuit terminal 1.
4. Using a scanning device, send the "on" and "off" commands to the EGR purge valve. The control lamp should light and go out in accordance with the commands sent.
• If the indicator lamp is constantly on, check the control circuit for a short to ground. If no fault is found when testing the circuit, replace the ECM.
• If the test lamp is always off, test the control circuit for a short to a live wire or an open/high resistance. If no fault is found when testing the circuit, replace the ECM.
5. If no fault is detected when testing all circuits, check or replace the EGR purge valve.

1. Turn off ignition, disconnect harness connector at EGR purge valve. Measure resistance between control circuit and ignition voltage circuit 1 of purge valve. This resistance should be 24-28 ohms.
• If the resistance is not within the specified range, replace the EGR purge valve.
2. Test for infinite resistance between each of the EGR purge valve contacts and the purge valve body.
• If the resistance is less, replace the EGR purge valve.

• FTP sensor signal voltage is not within calibrated range during cold start.
• The FTP sensor signal does not change by a calibrated amount during the purge process.
• The FTP sensor signal fluctuates more than a calibrated amount when the vehicle speed is less than 30 km/h (50 mph).

FTP sensor signal	Fuel tank pressure sensor voltage
High, approximately 1.5V or more	Negative pressure / vacuum
Low, approximately 1.5V or less	Positive pressure

• Diagnostic trouble codes P0101, P0102, P0103, P0116, P0117, P0118, P0119, P0125, P0449, P0498, P0506, P0507, P0721, P0722, P2227, P2228, and P2229 are not set.
• The fuel level is in the range of 12-88 percent.
• Engine coolant temperature at start-up is less than 35°C (95°F).
• The speed of the car is within 10-30 km/h (6-19 mph).
• The ECM commands the purge.
• The ratio of ambient pressure to design pressure in the manifold is less than 0.8.
• DTC P0451 will run continuously if the above conditions remain true for approximately 100 seconds.

• A clogged or restricted evaporative emission canister may cause this diagnostic trouble code to set.
• This diagnostic trouble code may be caused by a large leak in the evaporative emission canister.

1. Remove the fuel filler cap. Attach GE-41415-50 to the fuel tank filler neck. Attach J 41413-200 to J 41415-40.
2. Seal the system using the Purge Seal function of the scan tool.
3. Fill the fuel vapor capture system with nitrogen at a pressure of 5 inches H2O. Compare the signal of the fuel tank pressure sensor on the scanning device with the readings of the pressure gauge / vacuum gauge J 41413-200. The parameter of the FTP sensor on the scanning device must not differ from the reading of the pressure gauge/vacuum gauge by no more than 1 inch of H2O.
• If the FTP sensor reading differs from the pressure/vacuum gauge reading by more than 1 inH2O, replace the FTP sensor.
4. Using a scanning device, send a command to open the ventilation electromagnetic valve.
• If the FTP sensor parameter is not 0 in H20, replace the FTP sensor.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
Reference voltage 5V	P0122, P0452	P0452	P0453	-
FTP sensor signal	P0452	P0452	P0452	-
Low reference voltage	-	-	-	-

FTP sensor signal voltage	Fuel tank pressure
High, approximately 1.5V or more	Negative pressure / vacuum
Low, approximately	Positive pressure

• The ignition is on or the engine is running.
• Diagnostic tests are performed continuously when the above conditions are met.

1. Ignition on, monitor the FTP sensor voltage parameter. The FTP sensor voltage should be within 0.2-4.8 V.
2. If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.

1. Turn off the ignition, disconnect the harness connector from the FTP sensor.
2. Turn ignition off, check for resistance below 5.0 ohms between the low reference circuit and ground.
• If resistance is greater than the specified value, test the low reference circuit for an open/high resistance. If circuit and connections are normal, replace the engine control module (ECM).

Important: The 5-volt reference circuits are internally and externally connected to the ECM. Other component DTCs may be set. If other DTCs are set, use the electrical diagram to identify the appropriate circuits and components.

3. Ignition on, check for 4.8-5.2V between the 5V reference circuit and ground.
• If voltage is less than the specified range, test the 5V reference circuit for a short to ground or an open/high resistance. If circuit/connections test normal, replace the ECM.
• If the voltage is higher than the specified range, check the 5 V reference circuit for a short circuit to power. If no fault is detected during circuit / connection testing, replace the ECM controller.
4. Make sure the FTP sensor parameter is less than 4.8V
• If voltage is greater than specified, test signal circuit for short to power. If circuit/connections test normal, replace ECM.
5. Ignition on, connect a jumper wire with a 3 A fuse between the signal circuit and the 5 V reference circuit. Verify that the FTP sensor parameter is greater than 4.8 V.
• If the voltage is lower than the specified value, check the signal circuit for ground short-circuit or break/high resistance. If no fault is detected during circuit / connection testing, replace the ECM controller.
6. If the voltage is lower than the specified value, check the signal circuit for ground short-circuit or break/high resistance. If no fault is detected during circuit / connection testing, replace the ECM controller.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
Fuel Level Sensor Reference Voltage Circuit	P0462	-	-	P0461
Fuel level sensor signal circuit	P0462	P0463 1 P0464	P0463	P0461
Fuel Level Sensor Low Reference Circuit	-	P0463 1 P0464	P0463	P0461
Fuel gauge is inaccurate or does not work

• The ignition is on, the engine is running.
• The system voltage is within 9-16 volts.

• The sensor output voltage is less than 0.5 volts.
• The above condition persists for more than 30 seconds.

1. Turn off the ignition, disconnect the harness connector from the fuel level sensor.
2. Turn the ignition on and check with a scan tool if the Fuel Tank Level parameter is less than 4 percent.
• If the value is greater than 4 percent, check the signal circuit for a short to ground. If no fault is found when testing the circuit, replace the ECM.
3. If no fault is found when testing all circuits, replace the fuel level sensor.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
Fuel Level Sensor Reference Voltage Circuit	P0462	-	-	P0461
Fuel level sensor signal circuit	P0462	P0463 1 P0464	P0463	P0461
Fuel Level Sensor Low Reference Circuit	-	P0463 1 P0464	P0463	P0461
Fuel gauge is inaccurate or does not work

1. Turn off the ignition, remove the fuel level sensor and make sure there are no obstructing objects affecting the fuel level sensor.
• Remove detected interference.
2. If there is no interference, replace the fuel level sensor.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
Fuel Level Sensor Reference Voltage Circuit	P0462	-	-	P0461
Fuel level sensor signal circuit	P0462	P0463 1 P0464	P0463	P0461
Fuel Level Sensor Low Reference Circuit	-	P0463 1 P0464	P0463	P0461
Fuel gauge is inaccurate or does not work

• The ignition is on, the engine is running.
• The system voltage is within 9-16 volts.

• The sensor output voltage is less than 0.5 volts.
• The above condition persists for more than 30 seconds.

1. Turn off the ignition, disconnect the harness connector from the fuel level sensor.
2. Turn the ignition on and check with a scan tool if the Fuel Tank Level parameter is less than 4 percent.
• If the value is greater than 4 percent, check the signal circuit for a short to ground. If no fault is found when testing the circuit, replace the ECM.
3. If no fault is found when testing all circuits, replace the fuel level sensor.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
Fuel Level Sensor Reference Voltage Circuit	P0462	-	-	P0461
Fuel level sensor signal circuit	P0462	P0463 1 P0464	P0463	P0461
Fuel Level Sensor Low Reference Circuit	-	P0463 1 P0464	P0463	P0461
Fuel gauge is inaccurate or does not work

• The ignition is on, the engine is running.
• The system voltage is within 9-16 volts.

• The sensor output voltage is more than 3.5 volts.
• The above condition persists for more than 30 seconds.

1. Turn off the ignition, disconnect the harness connector from the fuel level sensor.
2. Check the resistance between the low reference circuit and a known ground, it should be less than 1.0 ohm.
• If greater than 1.0 ohms, then check the low reference voltage circuit for a short circuit to a live wire or for open / high resistance. If no fault is detected during circuit testing, then replace the ECM controller.
3. Turn ignition on, connect a jumper wire with a 3-amp fuse between the signal circuit and the low reference circuit. Verify with a scan tool that the "Fuel Level in Tank" parameter value is greater than 98 percent.
• If the voltage is less than 98 percent, then check the signal circuit for a short circuit to a live wire or for open / high resistance. If no fault is detected during circuit testing, then replace the ECM controller.
4. If no fault is found when testing all circuits, replace the fuel level sensor.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire
Cooling Fan Relay Control Circuit Low Speed	P0480	P0480	P0480
Cooling Fan Relay Coil Supply Voltage Circuit Low Speed	P0480	P0480	P0480
Cooling Fan Relay Control Circuit High Speed	P0481	P0481	P0481
Cooling Fan Relay Coil Supply Voltage Circuit High Speed	P0481	P0481	P0481

• Ignition in the "ON" position.
• The system voltage is between 9-18 volts.

• An abnormal voltage level has been detected in the cooling fan relay control circuit.
• This fault must exist for at least 30 seconds.

1. Turn off the ignition, disconnect the fan relay.
2. Turn on the ignition, make sure that the test lamp connected between the ground contact and a reliably known ground does not light.
• If the test lamp is on, check the control circuit for a short to a live wire.
3. Turn on the ignition, turn on the test lamp between the control circuit contact and a reliably known "ground". Use the scanning device to give the relay the "on" and "off" commands. The test lamp should light and go out in accordance with the given commands.
• If the test lamp is constantly on, check the relay control circuit for a short to a live wire. If no fault is found when testing the circuit, replace the ECM.
• If the test lamp does not light continuously, check the relay control circuit for a short to ground or an open/high resistance. If no fault is found when testing the circuit, replace the ECM.
4. Turn on the test lamp between the "+" terminal of the battery and a reliably known "ground".
• If the test lamp does not light, check the positive terminal of the battery for a short to ground or an open/high resistance.
5. Connect a 30 A fuse between the positive terminal of the battery and the fan power supply circuit contact and check that the fan turns on.
• If the fan does not turn on, check the fan power supply circuit for a short to ground or an open/high resistance. If the circuit is normal, replace the fan.
6. If all circuits are normal, then replace the relay.

• No MAP sensor diagnostic codes are set.
• No TP sensor diagnostic codes are set.
• The engine vacuum is 0-105 kPa (0-15 psi).
• The engine torque is 54-542 Nm (40-400 lb-ft).
• The TP angle is greater than 12 percent.
• Engine speed is above 3000 rpm.
• The transmission is not in PARK or NEUTRAL position (neutral).

1. Start the engine and operate the vehicle within the conditions for which the trouble code was set. The P0500 trouble code should not set.

1. Turn on the ignition with the engine off.
2. Disconnect the VSS vehicle speed sensor.
3. Connect a digital multimeter between the power terminal on the VSS harness connector and a good ground.
• If voltage is below 4.9V, test VSS supply circuit for short to ground or open/high resistance.
• If the voltage is greater than 5.2 V, check the VSS sensor power supply circuit for a short to supply voltage.
• If the VSS sensor circuit is normal and the voltage is outside the specified range, replace the ECM.
4. Connect a 3A fused jumper wire between the VSS sensor signal circuit and the low reference circuit.
• Monitor the sensor parameters by connecting and disconnecting the jumper between the VSS sensor signal circuit and the low reference circuit.
• The VSS sensor value should toggle between the upper and lower limits.
• If the VSS signal does not switch between the high and low limits, the ECM must be replaced.
• If the VSS signal switches between the high and low limits, the VSS sensor must be replaced.

• Before the ECM will report DTC P0506 or P0507, DTCs P0722 and P0723 must pass.
• DTCs P0111, P0112, P0113, P0116, P0117, P0118, P0119, P0121, P0122, P0123, P0221, P0222, P0223, P0442, P0443, P0446, P0455, P0458, P0459, P0496, P0722, and P0723 are not set.
• Fill factor less than 35% (only for DTC P0506).
• The vehicle speed is 0 km/h (0 mph).
• The purge valve of the fuel vapor recovery system (FEVAP) canister is turned off.
• Intake air temperature (IAT) is above -10.5°C (+13°F).
• Engine coolant temperature (ECT) is above -10.5°C (+13°F).
• The vehicle speed was detected before diagnostics were performed.
• DTC P0506 and P0507 will set continuously if the above conditions persist for more than 10 seconds.

• The actual engine speed is greater than the desired idle speed by at least 200 rpm for 4 seconds.

OR

• The ECM controller detects 3 fuel cut-offs due to over - revving the engine at idle.

1. Check DTC data with a scan tool.
• If there are any established diagnostic trouble codes for the throttle actuator control, throttle position sensor, or accelerator pedal position, please refer to the relevant DTC information.
2. Run the engine within the DTC Setting Conditions for 1 minute. DTCs P0506 and P0507 should not set.

• If the idle speed does not increase and decrease evenly, make sure that none of the following conditions exist:
• Vacuum leak
• Correct operation of the throttle valve - a throttle valve that is not completely closed will cause this fault code to be generated.
• Obstructions in the air intake system
• Throttle body for damage or unqualified intervention
• PCV valve malfunction or failure
• Excessive carbon deposits on the throttle body
• Parasitic load on the engine - for example, gearbox failure, accessory drive belt failure
• Restore the state as needed.

1. When the ignition is turned on or a door is opened using the remote key, the BCM and key exchange security data to confirm that the correct key is being used.
2. Once the correct key is confirmed and the ignition is turned on, the BCM and ECM communicate to allow the engine to start.
3. Different data encryption procedures are used during data exchange with each device.

• If the key is not programmed into the BCM, key authentication fails and the vehicle is immobilized.
• If the BCM is not linked to the ECM, the ECM will fail to authenticate to the BCM and the vehicle will be disabled.
• If the BCM, key, or ECM memory is corrupted, authentication will fail and the vehicle will be immobilized.
• If there is a problem with the GMLAN network, authentication will fail and the vehicle will be locked.

Important: To check the correctness of the communication between the vehicle theft deterrent system (VTD) and the ECM, the existing fault codes of type "B" (related to anti-theft system) must be diagnosed before diagnosing type "P" fault codes.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
Engine Oil Pressure Sensor 5V Reference Circuit	P0522	P0522	P0523	P0521
Engine Oil Pressure Sensor Signal Circuit	P0522	P0523	P0523	P0521
Low reference voltage	-	P0523	-	P0521

• The ECM detects that the EOP sensor circuit signal level is below a specified value.
• This condition persists for more than 10 seconds.

1. Turn off ignition, disconnect wiring harness connector from engine oil pressure (EOP) sensor.
2. Ignition on, check for 4.8-5.2V between the 5V reference circuit and ground.
• If less than 4.8 V, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit is OK, replace the ECM.
• If voltage is greater than 5.2 V, test 5 V reference circuit for short to supply voltage. If circuit tests normal, replace ECM.
3. Using a scan tool, verify that the engine oil pressure sensor reading is greater than 550 kPa (80 psi).
• If less than 550 kPa, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM.
4. If all circuits are OK, check or replace the EOP sensor.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
Engine Oil Pressure Sensor 5V Reference Circuit	P0522	P0522	P0523	P0521
Engine Oil Pressure Sensor Signal Circuit	P0522	P0523	P0523	P0521
Low reference voltage	-	P0523	-	P0521

• The ECM detects that the voltage on the EOP sensor signal circuit is less than 0.1 V.
• This condition persists for more than 10 seconds.

1. Turn off ignition, disconnect wiring harness connector from engine oil pressure (EOP) sensor.
2. Ignition on, check for 4.8-5.2V between the 5V reference circuit and ground.
• If less than 4.8 V, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit is OK, replace the ECM.
• If voltage is greater than 5.2 V, test 5 V reference circuit for short to supply voltage. If circuit tests normal, replace ECM.
3. Using a scan tool, verify that the engine oil pressure sensor reading is greater than 550 kPa (80 psi).
• If less than 550 kPa, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM.
4. If all circuits are OK, check or replace the EOP sensor.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
Engine Oil Pressure Sensor 5V Reference Circuit	P0522	P0522	P0523	P0521
Engine Oil Pressure Sensor Signal Circuit	P0522	P0523	P0523	P0521
Low reference voltage	-	P0523	-	P0521

• The ECM detects that the voltage on the EOP sensor signal circuit is greater than 4.4 V.
• This condition persists for more than 10 seconds.

1. Turn off ignition, disconnect wiring harness connector from engine oil pressure (EOP) sensor.
2. Turn ignition off, test for less than 1 ohm resistance between the low reference circuit and a good ground.
• If the value is greater than 1 ohm, check the low reference circuit for a supply voltage short circuit or open / high resistance. If no fault is detected during circuit testing, then replace the ECM controller.
3. Turn on ignition, check for 4.8-5.2V between 5V reference circuit and good ground.
• If less than 4.8 V, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit is OK, replace the ECM.
• If voltage is greater than 5.2 V, test 5 V reference circuit for short to supply voltage. If circuit tests normal, replace ECM.
4. Connect a 3-amp fused jumper wire between the signal circuit and the low reference circuit. Using a scan tool, verify the engine oil pressure sensor value is less than 8 kPa (1.2 psi).
• If the value is greater than 8 kPa, check the signal circuit for supply voltage short-circuit or open / high resistance. If no fault is detected during circuit testing, then replace the ECM controller.
5. If all circuits are OK, check or replace the EOP sensor.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
Air Conditioning (A/C) Refrigerant Pressure Sensor Signal Circuit	P0532	P0532	P0533	-
5V Reference Voltage Circuit	P0532	P0532	-	-
Low level reference chain	-	P0533	-	-

• The engine is running
• Any of the fault code conditions persists for 15 seconds.
• Battery voltage is within 11-18 V.

• The ECM detects that the A/C pressure is less than 1 psi (0.01 V).
• The ECM detects that the A/C pressure is greater than 428 psi (4.92 V).

1. Turn off the ignition, disconnect the air conditioning pressure sensor wiring harness connector.
2. Turn ignition off, check for less than 1 ohm resistance between the low reference circuit terminal and ground.
• If resistance is greater than 1 ohm, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
3. Turn on the ignition, check for voltage of 4.8-5.2 V between the contact of the 5 V reference voltage circuit and ground.
• If less than 4.8 V, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit is OK, replace the ECM.
• If voltage is greater than 5.2 V, test 5 V reference circuit for short to supply voltage. If circuit tests normal, replace ECM.
4. Using a scan tool, verify that the A/C High Pressure Sensor reading is less than 428 psi.
• If greater than 428 psi, test the signal circuit for a short to supply voltage. If the circuit tests normal, replace the ECM.
5. Connect a 3-amp fused jumper wire between pin 3 of the signal circuit and pin 2 of the 5-volt reference circuit. Using a scan tool, verify that the A/C high pressure sensor reading is greater than 428 psi.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
Ignition 1 Signal (Ignition signal 1)	P0562	P0562	-	-

• The vehicle speed is greater than 8 km/h (5 mph).
• The system voltage is in the range of 9.5-18 V.

1. Measure the battery voltage and compare it to the ignition voltage signal parameter in the ECM data list. Make sure that the battery voltage and the ignition voltage signal reading differ by no more than 1 V.
• If the difference is greater than 1 V, test the ignition circuit at the ECM for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
Ignition 1 Signal (Ignition signal 1)	P0562	P0562	-	-

• The vehicle speed is greater than 8 km/h (5 mph).
• The system voltage is in the range of 9.5-18 V.

1. Measure the battery voltage and compare it to the ignition voltage signal parameter in the ECM data list. Make sure that the battery voltage and the ignition voltage signal reading differ by no more than 1 V.
• If the difference is greater than 1 V, test the ignition circuit at the ECM for a short to ground or an open/high resistance. If the circuit is OK, replace the ECM.

• The vehicle speed is greater than 8 km/h (5 mph).
• The system voltage is in the range of 9.5-18 V.

• A possible cause for this fault code may be overcharging the battery or starting the engine from an external voltage source.

1. Measure the battery voltage and compare it to the ignition circuit signal parameter in the ECM data list. Verify that the battery voltage and the ignition voltage signal reading differ by no more than 1 V.
• If the difference is greater than 1 V, test the ignition circuit at the ECM for a short to voltage or an open/high resistance. If the circuit is OK, replace the ECM.

• The vehicle speed was varied in the range 0-60 km/h (0-37 mph) 3 times in 1 ignition cycle.
• Constantly, if the above conditions were met.

• The TCM detects voltage on the TCC/brake/cruise control switch signal circuit when the circuit should be open.

1. Turn off the ignition, connect the scanning device.
2. Make sure no other fault codes are set.
3. Turn ignition on, use a scan tool to observe the Torque Converter Clutch (TCC)/Brake Switch parameter in the Transmission TCC Data List.
• The TCC/Brake Switch parameter should indicate an "open" condition. If the condition is "closed", test the TCC/Brake/Cruise Control Switch circuit for a short to voltage.
• If all circuits are good, replace the BCM.
4. Turn on the ignition, observe the scanning device, press the brake pedal.
• The TCC/Brake Switch parameter should show a closed condition. If it shows an open condition, test the TCC/Brake/Cruise Control circuit to the ECM for a short to ground or an open/high resistance.
• If all circuits are OK, replace the ECM.
5. If all circuits are OK, replace the BPP sensor.

• If DTC P0601 or P0604 fails on this ignition cycle, replace the engine control module (ECM).

• Ensure all tools are securely attached.
• Ensure that the programming equipment operates correctly.
• Ensure that the correct software and calibration are used.
• Try to program the ECM.
• If DTC P0602 is set, replace the ECM.

• Read the fault logs with a scanning device.
• Use a scan tool to clear DTC codes.
• Turn off the ignition within 30 seconds.
• Condition the vehicle for running the DTC. You can also condition the vehicle to run the conditions that were observed based on the recorded malfunction data.
• If DTC P0606 fails on this ignition cycle, replace the ECM.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
Controller chain	Minor code	Minor code	Senior code	-
Winding side supply voltage circuit	Minor code	Minor code	-	-

• The ECM detects an abnormal voltage level in the control circuit or output circuit that operates the starter relay.

• Ignition system trouble codes are set when the ignition switch is in the "start" position and the starter relay or starter is inoperative. When the ECM allows the starter to operate. If a condition exists that prevents the engine from starting, the ECM will not receive input from the CKP and CMP sensors and trouble codes will be set.
• Reviewing the fault history since the last failed diagnostic test can help diagnose the fault. This information can help determine how often the condition that sets the fault code occurs.

1. Turn on the ignition, use a scanning device to command the starter relay to turn on and off. Check by touch or by ear that each relay turns on and off when commanded.

1. Turn off the ignition, disconnect the starter relay.
2. Turn on the ignition, make sure that the test lamp does not light between the corresponding contacts and a reliable ground.
• If the test lamp is on, check the signal circuit for a short to supply voltage.
3. Turn on the ignition. Connect a test lamp between the control circuit terminal and a reliable ground. Using a scan tool, command the relay to turn on and off. The test lamp should light and go out in accordance with the commands given.
• If the test lamp is constantly on, check the relay control circuit for a short to supply voltage. If the circuit is OK, replace the ECM/
• If the test lamp does not illuminate at all, test the relay control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
4. Connect a test lamp between the "B+" voltage contact and a reliable ground.
• If the test lamp does not illuminate, check the battery voltage circuit "B+" for a short to ground or an open/high resistance.
5. Disconnect the starter motor winding wire from the starter, connect a test lamp between the starter winding wire and a reliable ground. Connect a jumper with a 10 A fuse between the positive terminal of the battery and the contact of the starter motor power circuit, make sure that the test lamp lights up.
• If the test lamp does not light, check the starter motor winding power supply circuit for a short to ground or an open/high resistance. If all circuits are normal, replace the relay.

• The vehicle speed is greater than 8 km/h (5 mph).
• The system voltage is in the range of 9.5-18 V.

1. Turn off the ignition, disconnect the generator harness connector.
2. With the ignition on and the engine off, connect the test lamp to the positive voltage of the battery and repeatedly check the generator excitation duty cycle circuit from the harness side with a probe, observing the signal parameter on the generator F-terminal in the ECM data list. The value should change from 0 to a value greater than 95%.
• If the generator F-terminal signal parameter does not change when the test lamp is connected, check the generator F-terminal signal circuit for a short to ground or an open/high resistance. If the circuit is OK, replace the ECM.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
Fuel Pump Relay Control	P0628	P0627	P0629	-
Fuel pump weight	-	P0627	-	-
Battery Voltage - Relay Switch	1	2	-	-
Fuel pump supply voltage	1	2	3	-
The fuel relay fuse opens, the engine cranks, but the engine does not start. The engine crankshaft turns, but the engine does not start. The fuel pump runs continuously, the battery is discharged.

• Ignition on, engine off.
• Ignition voltage 1 is greater than 10.5 V.
• The ECM has commanded the fuel pump relay on and off at least once during the ignition cycle.
• The above conditions occur for more than 1 second.
• Diagnostic tests are performed continuously when the above conditions are met.

1. Turn off the ignition, disconnect the fuel pump relay.
2. Connect a test light between the fuel pump relay control circuit and the negative battery terminal.
3. Ignition on, use a scan tool to command the fuel pump to turn on and off. The indicator lamp should turn on and off according to the control commands.
• If the test lamp remains off all the time, test the control circuit for a short to ground or an open/high resistance. If the circuits and connectors are OK, replace the ECM.
• If the test lamp is always on, test the control circuit for a short to supply voltage. If the circuit/connections test normal, replace the ECM.
4. Turn off the ignition, connect a test lamp between the fuel pump relay control circuit and the fuel pump relay ground circuit.
5. Ignition on, use a scan tool to command the fuel pump to turn on and off. The indicator lamp should turn on and off according to the control commands.
• If the test lamp does not come on when commanded to turn on, repair open/high resistance in the fuel pump relay ground circuit.
6. If checking all circuits/connections reveals no fault, check or replace the fuel pump relay.

1. Measure the resistance between terminals 85 and 86 of the fuel pump relay; the resistance should be within 70 - 110 Ohms.
• If the resistance is not within the specified range, replace the fuel pump relay.
2. Measure the resistance between the following terminals of the fuel pump relay; the resistance must be infinite.
• 30 and 86
• 30 and 87
• 30 and 85
• 85 and 87
• If a connection is found, replace the fuel pump relay.
3. Connect a jumper wire with a 20 A fuse between the positive battery terminal and terminal 85 of the fuel pump relay. Connect a jumper wire between the negative battery terminal and terminal 86 of the fuel pump relay. Measure the resistance between terminals 30 and 87 of the fuel pump relay; the resistance should be less than 2 ohms.
• If the resistance is greater than 2 ohms, replace the fuel pump relay.

• The ignition is on or the engine is running.
• Ignition voltage 1 is greater than 7 V.
• DTCs P0638 and P2102 run continuously if the above conditions are met for more than 1 second.

• Before the ECM will report DTC P2100, DTC 2101 must successfully clear.
• The ignition is on or the engine is running.
• DTC P2100 runs continuously if the above conditions are met for more than 1 second.

• The ignition is on.
• The car's speed is 0 km/h (0 mph).
• Engine speed is below 40 rpm.
• Engine coolant temperature (ECT) between 5-85°C (41-185°F).
• Intake air temperature (IAT) within 5-60°C (41-140°F).
• Ignition voltage 1 exceeds 10 V.
• Accelerator pedal position (APP) is less than 15%.
• DTC P2119 sets once per ignition cycle if the above conditions are present for less than 1 second.

• The ECM detects that the duty cycle for the upper limit of the test range is greater than 80% for more than 0.6 s.

OR

• The ECM detects that the duty cycle for the lower limit of the test range is greater than 80% for more than 5 s.

• The ECM detects that the TAC motor output driver does not turn off when commanded off.
• The condition lasts less than 4 seconds.

• The ECM detects that the difference between the commanded and actual throttle position is greater than 10%.
• This condition lasts less than 4 seconds.

1. If the ignition is switched on, monitor the information about diagnostic trouble codes using the scanning device. Make sure that the diagnostic trouble codes P0121, P0122, P0123, P0221, P0222 or P0223 are not set.
• If any of these DTCs are set, proceed to further diagnostics for DTC P0121, P0122, P0123, P0221, P0222, or P0223.
2. Using a scan tool, verify that the TP 1 sensor voltage is between 0.2-0.9 V and that the TP 2 sensor voltage is between 4.2-4.8 V.
• If any of the TP sensor voltages are not within the specified range, proceed to further diagnostics for DTC P0121, P0122, P0123, P0221, P0222, or P0223.
3. Quickly depress the accelerator pedal from the rest position to the wide open throttle (WOT) position and release the pedal. Repeat this procedure several times. DTC P0638, P2111, P2112, or P2119 should not set.
• If any of the DTCs P0121, P0122, P0123, P0221, P0222, or P0223 are set while performing this procedure, proceed to further diagnostics for DTCs P0121, P0122, P0123, P0221, P0222, or P0223.
4. Slowly press the accelerator pedal until the throttle valve is fully open, and then slowly return the pedal to the closed throttle position. Repeat this procedure several times. DTC P0638, P2111, P2112, or P2119 should not set.
• If any of the DTCs P0121, P0122, P0123, P0221, P0222, or P0223 are set while performing this procedure, proceed to further diagnostics for DTCs P0121, P0122, P0123, P0221, P0222, or P0223.
5. If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the status data records/failure logs can also be met.

1. Check the throttle body for the following faults:
• The throttle valve is not in its original position
• Throttle valve stuck open or closed
• The throttle valve opens or closes without spring pressure
• If a fault is found, replace the damaged throttle body.

Important: Disconnecting the throttle body wiring harness connector will cause additional DTCs to be set.

2. Turn off ignition, disconnect harness connector from throttle body. Ignition on, measure voltage of control circuits of motors 1 and 2; the voltage should be 2-4 V.
• If the voltage is less than 2 V, check the control circuit of the appropriate motor for an open circuit or short to ground. If the circuit is OK, replace the ECM.
• If voltage is greater than 4 V, test the appropriate motor control circuit for a short to supply voltage. If circuit testing does not reveal a fault, replace the ECM.
3. Turn off ignition, connect the injector test lamp between the TAC 1 motor control circuit and the TAC 2 motor control circuit of the throttle body harness connector. Watching the injector test lamp, turn on the ignition for 5 seconds and turn it off. Make sure that the injector test lamp lights up brightly.
• If the injector warning lamp does not come on, check for a short circuit between the TAC motor 1 and TAC motor 2 control circuits. If no fault is found when testing the circuit, replace the ECM.
4. If all circuits are normal, replace the throttle body.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire
Air Conditioner (A/C) Clutch Relay Control Circuit	P0646	P0645, P0646	P0647
Air Conditioner (A/C) Clutch Relay Coil Supply Voltage Circuit	P0646	P0645, P0646	P0647

• The ignition is on.
• The voltage in the system is within 9-18 V.

• An incorrect voltage level was detected in the air conditioning control circuit.
• This condition must be maintained for at least 30 seconds.

1. Turn off the ignition, disconnect the harness connector from the air conditioning compressor.
2. Turn on the ignition, make sure that the control lamp lights up between the voltage contact "B+" and a reliable ground.
• If the test lamp does not illuminate, test the "B+" voltage circuit for a short to ground or an open/high resistance. If the circuit is OK, replace the ECM
3. Turn on the ignition, use the scanning device to issue a command to turn on the air conditioning compressor. Check that the test lamp lights up between the "B+" voltage circuit and the control circuit.
• If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit is OK, replace the ECM
4. If all circuits are OK, Replace the air conditioning compressor clutch.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
Supply voltage of the malfunction indicator lamp	P0650	P0650	-	-
Control of the malfunction indicator lamp	P0650/MIL ON	P0650	P0650	-

• Engine speed is more than 80 rpm
• Ignition voltage 1 within 10-18 volts.
• The ECM has commanded the MIL to turn on and off at least once during the ignition cycle.
• DTC P0650 runs continuously after the specified conditions are met.

• The ECM detects an open circuit, short to ground, or short to battery voltage in the MIL control circuit.
• This condition lasts for at least 4 seconds.

1. If any other instrument cluster indicators or gauges do not work, See Section 9E, Instruments/Driver Information.
2. Turn off ignition, disconnect ECM wiring harness connectors. Turn on ignition, malfunction indicator lamp should not light.
• If the fault indicator light is on, check the control circuit of the fault indicator light for a short-circuit to ground.
3. Turn on the ignition, connect a jumper wire with a 3 A fuse between the control circuit of the malfunction indicator lamp and the negative terminal of the battery. The malfunction indicator lamp should light.
• If the MIL does not illuminate, test the MIL control circuit for a short to battery voltage or an open/high resistance. If the circuit is normal, replace the instrument cluster/bulb.
4. If all circuits/connections are normal, replace the ECM.

Important: A main relay failure will cause multiple diagnostic trouble codes to be set. The diagnostic trouble codes listed in the table are only set if there is a main relay failure.

Chain	Short circuit with "ground"	High resistance	Breakup	Short circuit to live wire	Signal parameters
Supply voltage B+ - Winding	P0685	P0685	P0685	-	-
Supply voltage B+ - Switch	-	P0689	P0689	P0690	-
Relay control circuit	P0686	P0685	P0685	P0687	P0685
Ignition Voltage Circuit 1	-	P0689	P0689	P0690	-

• ECM fuse or HFV6 ECM fuse
• ETC fuse
• PRE O2/CAM fuse
• POST O2 fuse
• Fuse EVEN INJ/COIL
• ODD INJ/COIL Fuse

• Battery voltage is within 10.5-18 volts.
• Turn off the ignition.
• A command has been given to turn off the main relay.
• Diagnostic tests are performed continuously when the above conditions are met.

• Battery voltage is within 10.5-18 volts.
• Ignition in the "ON" position.
• The command to turn on the main relay has been given.
• These DTCs run continuously after the specified condition is met.

• The specified state of the output driver module and the actual state of the control circuit do not match.

OR

• The ECM detects that the main relay feedback circuit voltage is not within the expected range when the main relay is commanded on or off.
• One of these conditions occurs for more than 2 seconds.

• This test procedure requires that the vehicle's battery has been load tested and is fully charged. See Battery Inspection/Test in the Engine Electrical section.
• When disconnecting electrical connectors or removing fuses and relays from the fuse box, always check the component terminals for corrosion and the paired electrical contacts for tight contact.
• For tests that require connections to underhood fuse block terminals, component harness connector terminals, or ECM harness connector terminals, use the J 35616 Connector Test Adapter Kit.

1. Turn ignition on, clear DTC codes with scan tool.
2. Turn off the ignition for 30 seconds.
3. Ignition on, retrieve DTC information with scan tool.
4. Check the diagnostic trouble code information with a scan tool. DTC P0685, P0686, P0687, P0689, or P0690 should not be set.

1. Turn off ignition, disconnect ignition relay or main engine control relay.

Important: A pilot lamp is used to create a load in the circuit, which may not light.

2. Connect a test lamp between the B+ power supply circuit on the main relay winding side and the negative terminal of the battery.
3. Turn ignition on, check voltage between main relay B+ voltage circuit and battery positive terminal; the voltage should be less than 0.1 V.
• If voltage is greater than 0.1 V, repair B+ voltage circuit on main relay coil side for short to ground or open/high resistance.

Important: A pilot lamp is used to create a load in the circuit, which may not light.

4. Connect a test lamp between the B+ voltage circuit on the main relay switch side and the negative battery terminal.
5. Turn ignition on, check voltage between main relay B+ voltage circuit and battery positive terminal; the voltage should be less than 0.1 V.
• If voltage is greater than 0.1 V, repair the B+ voltage circuit at the main relay switch side for a short to ground or open/high resistance.
6. With the ignition on, connect a test lamp between the main relay control circuit and the B+ voltage supply circuit from the main relay winding side.
7. Turn on the ignition. The indicator lamp should come on when the ignition switch is turned to the "on" position and go out when the ignition switch is turned to the "off" position.
• If the test lamp is constantly on, check the control circuit for a short to ground. If no fault is found when testing the circuit/connections, replace the ECM.
• If the test lamp does not illuminate continuously, test the control circuit for a short to a live wire or an open/high resistance. If no fault is found when testing the circuit/connections, replace the ECM.

Important: The ignition voltage circuit 1 connects the main relay and the ECM. The ignition voltage circuit 1 is a feedback circuit.

8. Connect a jumper wire with a 15 A fuse between the B+ supply voltage circuit and the main relay ignition 1 voltage circuit.
9. Try to start the engine. The engine should start.
• If the engine does not start, test the ignition 1 voltage circuit between the main relay and the ECM for a short to ground or an open/high resistance. If the circuit/connections test normal, replace the ECM.
10. If checking all circuits/connections reveals no fault, check or replace the main relay.

1. Measure the resistance between terminals 85 and 86 of the main relay; the resistance should be within 70 - 110 Ohms.
• If the resistance is not within the specified range, replace the main relay.
2. Measure the resistance between the following terminals of the main relay; the resistance must be infinite.
• 30 and 86
• 30 and 87
• 30 and 85
• 85 and 87
• If continuity is found, replace the main relay.
3. Connect a jumper wire with a 20 A fuse between the positive battery terminal and terminal 85 of the fuel pump relay. Connect a jumper wire between the negative battery terminal and terminal 86 of the fuel pump relay. Measure the resistance between terminals 30 and 87 of the fuel pump relay; the resistance should be less than 2 ohms.
• If the resistance is more than 2 ohms, replace the main relay.

• Ignition in the "ON" position.
• The system voltage is between 9-18 volts.

• A voltage level different from the required level was detected in the feedback circuit of the ignition relay of the engine management system.
• This fault must exist for at least 30 seconds.

1. Turn off the ignition, disconnect the ignition relay of the engine management system.
2. Turn on the ignition, make sure that the test lamp connected between the ground contact and a reliably known ground does not light.
• If the test lamp is on, check the control circuit for a short to a live wire.
3. Turn on the ignition, turn on the test lamp between the control circuit contact and a reliably known "ground". Use the scanning device to give the relay the "on" and "off" commands. The test lamp should light and go out in accordance with the given commands.
• If the test lamp is constantly on, check the relay control circuit for a short to a live wire. If no fault is found when testing the circuit, replace the ECM.
• If the test lamp does not light continuously, check the relay control circuit for a short to ground or an open/high resistance. If no fault is found when testing the circuit, replace the ECM.
4. Turn on the test lamp between the "+" terminal of the battery and a reliably known "ground".
• If the test lamp does not light, check the positive circuit of the battery for a short to ground or an open/high resistance.
5. Connect a 30 A fuse between the positive battery terminal and the power supply circuit contact of the ignition relay of the engine management system and check the circuit activation.
• If the circuit does not turn on, check the power supply circuit of the ignition relay of the engine management system for a short circuit to ground and for an open / high resistance. If the circuit is normal, replace the fan.
6. If all circuits are normal, then replace the relay.

• Ignition in the "ON" position.
• The system voltage is between 9-18 volts.

• An abnormal voltage level has been detected in the cooling fan relay control circuit.
• This fault must exist for at least 30 seconds.

1. Turn off the ignition, disconnect the corresponding fan relay.
2. Turn on the ignition, make sure that the test lamp connected between the ground contact and a reliably known ground does not light.
• If the indicator lamp is on, check the ground connection circuit for a short circuit to a live wire.
3. Turn on the ignition, turn on the test lamp between the control circuit contact and a reliably known "ground". Use the scanning device to give the relay the "on" and "off" commands. The test lamp should light and go out in accordance with the given commands.
• If the test lamp is constantly on, check the relay control circuit for a short to a live wire. If no fault is found when testing the circuit, replace the ECM.
• If the test lamp does not light continuously, check the relay control circuit for a short to ground or an open/high resistance. If no fault is found when testing the circuit, replace the ECM.
4. Turn on the test lamp between the "+" terminal of the battery and a reliably known "ground".
• If the test lamp does not light, check the positive terminal of the battery for a short to ground or an open/high resistance.
5. Connect a 30 A fuse between the positive terminal of the battery and the fan power supply circuit contact and check that the fan turns on.
• If the fan does not turn on, check the fan power supply circuit for a short to ground or an open/high resistance. If the circuit is normal, replace the fan.
6. If all circuits are normal, then replace the relay.

• Ignition in the "ON" position.
• The system voltage is between 9-18 volts.

• An abnormal voltage level has been detected in the cooling fan relay control circuit.
• This fault must exist for at least 30 seconds.

1. Turn off the ignition, disconnect the corresponding fan relay.
2. Turn on the ignition, make sure that the test lamp connected between the ground contact and a reliably known ground does not light.
• If the indicator lamp is on, check the ground connection circuit for a short circuit to a live wire.
3. Turn on the ignition, turn on the test lamp between the control circuit contact and a reliably known "ground". Use the scanning device to give the relay the "on" and "off" commands. The test lamp should light and go out in accordance with the given commands.
• If the test lamp is constantly on, check the relay control circuit for a short to a live wire. If no fault is found when testing the circuit, replace the ECM.
• If the test lamp does not light continuously, check the relay control circuit for a short to ground or an open/high resistance. If no fault is found when testing the circuit, replace the ECM.
4. Turn on the test lamp between the "+" terminal of the battery and a reliably known "ground".
• If the test lamp does not light, check the positive terminal of the battery for a short to ground or an open/high resistance.
5. Connect a 30 A fuse between the positive terminal of the battery and the fan power supply circuit contact and check that the fan turns on.
• If the fan does not turn on, check the fan power supply circuit for a short to ground or an open/high resistance. If the circuit is normal, replace the fan.
6. If all circuits are normal, then replace the relay.

• The ignition is on or the engine is running.
• DTC P0700 runs continuously.

Important: Before diagnosing a TCM DTC, clear any existing engine control DTCs.

• The engine is running.
• The system voltage is between 9-18 volts.

• The ECM detects that 15 gear shifts have occurred with less than 3 clutch pedal switch operations.

1. Turn off the ignition, disconnect the clutch pedal switch at the switch.
2. Turn on the ignition, make sure that the test lamp is lit, connected between the signal contact and a reliably known "ground".
• If the test lamp does not illuminate, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
3. Connect a 10 Amp fuse between the signal circuit and the ground terminal at the wiring harness connector.
• The scanning device display should show the status "On" (Active).
• If the display remains "Inactive", check the ground circuit for a short to ground or an open/high resistance.
4. If all circuits are normal, then replace the clutch switch.

• Diagnostic trouble codes P0010, P0013, P0020, P0023, P2088, P2089, P2090, P2091, P2092, P2093, P2094, and P2095 are not set.
• The engine runs for more than 1 second.
• The ECM has completed the camshaft position actuator output driver test.
• Engine speed is more than 1000 rpm.
• DTCs P1011, P1012, P1013 and P1014 are only executed when the engine is started.

Important: The engine oil level and pressure are critical to the proper operation of the variable valve timing drive system. Before continuing with this diagnostic, ensure that the required oil level and pressure are present.

• Start the engine. Make sure there are no abnormal noises when the engine starts.
• Monitor DTC information with a scan tool. DTCs P1011, P1012, P1013, and P1014 should not be set.
• If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.
• Inform the customer that the following actions may cause DTC P1011, P1012, P1013, or P1014 to set:
• Engine shutdown with accelerator pedal depressed
• Turning off the engine while driving
• Pressing the accelerator pedal to start the engine

• If abnormal engine noise is present or DTCs P1011, P1012, P1013, or P1014 are set, replace the appropriate camshaft position actuator.

• The car's speed is 0 km/h (0 mph).
• Engine speed is less than 40 rpm.
• Engine coolant temperature (ECT) is between 5-85°C (41-185°F).
• The intake air temperature is between 5-60°C (41-140°F).
• Ignition voltage 1 is greater than 10 volts.
• Accelerator pedal position is less than 15%.
• DTC P1551 is set when the throttle actuator motor is disabled

• Controlling the throttle using the throttle position control function of the scanning instrument may cause additional diagnostic trouble codes to be set. DO NOT ATTEMPT to diagnose DTCs installed when using this feature.
• Among the scan tool's special functions is the Throttle Control System Control function. This function allows you to control the throttle position throughout its entire range of motion to verify that the throttle assembly and control system are operating correctly.
• Check the conditions under which the throttle valve can be considered open.
• Check for situations that may cause ice to form in the throttle bore.
• The throttle valve is spring loaded in the slightly open position. The throttle valve should be approximately 3-5 percent open. This is the normal position. The throttle valve should not be fully closed or open more than the specified amount. The throttle valve should move open and closed without binding under normal spring force. The throttle valve should NOT move freely open or closed WITHOUT spring force.

• Ignition ON, retrieve DTC information with a scan tool. Verify that DTCs P0121, P0122, P0123, P0221, P0222, P0223, P2100, P2101, or P2119 are not set.
• If one of the above DTCs is set, refer to the corresponding DTC information for further diagnosis.
• Monitor the DTC information with a scan tool for 30 seconds. DTC P1551 should not set.
• If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.

• The throttle valve is NOT in the home position
• Throttle valve stuck in open or closed position
• The throttle valve moves freely to the open or closed position WITHOUT spring force
• If a problem is found, replace the throttle body.

Important: Since there is normal communication between the TDM and ECM, theft deterrent type B codes must be set before the P codes.

1. When the ignition is turned on or a door is unlocked with the remote key, security data is exchanged between the BCM and the key to verify the key being used.
2. Once the key is confirmed to be correct and the ignition is turned on, data is exchanged between the BCM and the ECM to start the engine
3. Data exchange processes involve the exchange of various encrypted data between each of the devices.

Important: Failure to complete any of these password verification processes will result in the engine not being able to start and diagnostic trouble codes being stored. Additional information on the anti-theft system.

• If the key is not programmed into the BCM, then the key validation check will fail and the vehicle immobilizer will be activated.
• If the communication channel is not established between the BCM and the ECM, then the BCM will fail to check the ECM password and the vehicle immobilizer will be activated.
• If the BCM, key or ECM has a faulty memory, then the password verification process will fail and the vehicle immobilizer will be activated.
• If there is a fault in the GMLAN network, the password verification will not be performed and the vehicle immobilizer will be activated.

Important: Since there is normal communication between the TDM and ECM, theft deterrent related codes type B must be set before theft deterrent related codes type P. Perform the theft deterrent component programming procedure. The ECM should successfully complete learning the password and the engine should start.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
Generator L terminal circuit	P0621	P0621	P0621	P0621

1. With the ignition on and the engine off, disconnect the harness from the generator and measure the voltage of the generator turn-on circuit, which should be close to 0 volts.
• If more than 0 V, then check the generator turn-on circuit for a short to a live wire. If no fault is found when testing the circuit, then replace the ECM.
2. With the ignition on and the engine running, the voltage in the generator turn-on circuit must be greater than 3.5 volts.
• If there is no voltage, check the generator power circuit for a short to ground or an open/high resistance. If no fault is found when testing the circuit, replace the ECM.
3. If no fault is found when testing all circuits.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
Ignition voltage 1	P2009?	P2008	-	-
IMRC control circuit	P2009	P2008	P2010	-
?Opens the fuse which supplies voltage to the IMRC solenoid.

• The ignition is on or the engine is running.
• Diagnostic tests are performed continuously when the above conditions are met.

1. Turn ignition on, use scan tool to command IMRC solenoid on and off. There should be a noticeable and audible click.
2. If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.

1. Turn off ignition, disconnect harness connector from IMRC solenoid.
2. Turn ignition on, check battery voltage between IMRC solenoid 1 ignition voltage circuit and ground.
• If voltage is below B+, repair short to ground or open/high resistance in IMRC solenoid ignition 1 voltage circuit. Replace fuse if necessary.
3. Turn ignition off, connect a test lamp between the control circuit and the ignition voltage circuit 1 of the IMRC solenoid.
4. Turn ignition on, use scan tool to command IMRC solenoid ON. Test lamp should turn on and off.
• If the test lamp is constantly on, check the control circuit for a short to ground. If no fault is found when testing the circuit/connections, replace the ECM.
• If the test lamp does not illuminate at all, check the control circuit for a short to a live wire or an open/high resistance. If no fault is found when testing the circuit/connections, replace the ECM.
5. If checking all circuits/connections reveals no faults, replace the IMRC solenoid.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
Fuel Level Sensor Reference Voltage Circuit	P0462	-	-	P0461
Fuel level sensor signal circuit	P0462	P0463 1 P0464	P0463	P0461
Fuel Level Sensor Low Reference Circuit	-	P0463 1 P0464	P0463	P0461
Fuel gauge is inaccurate or does not work

• The ignition is on, the engine is running.
• The system voltage is within 9-16 volts.

• The sensor output voltage is less than 0.5 volts.
• The above condition persists for more than 30 seconds.

1. Turn off the ignition, disconnect the harness connector from the fuel level sensor.
2. Turn the ignition on and check with a scan tool if the Fuel Tank Level parameter is less than 4 percent.
• If the value is greater than 4 percent, check the signal circuit for a short to ground. If no fault is found when testing the circuit, replace the ECM.
3. If no fault is found when testing all circuits, replace the fuel level sensor.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
Fuel Level Sensor Reference Voltage Circuit	P2067	-	-	P2066
Fuel level sensor signal circuit	P2067	P2068	P2068	P2066
Fuel Level Sensor Low Reference Circuit	-	P2068	P2068	P2066

1. Turn off the ignition, disconnect the harness connector from the fuel level sensor.
2. Turn the ignition on and check with a scan tool if the Fuel Tank Level parameter is less than 4 percent.
• If the value is greater than 4 percent, check the signal circuit for a short to ground. If no fault is found when testing the circuit, replace the ECM.
3. Turn ignition on, connect a jumper wire with a 3-amp fuse between the signal circuit and the low reference circuit. Verify with a scan tool that the "Fuel Level in Tank" parameter value is greater than 98 percent.
• If the voltage is less than 98 percent, then check the signal circuit for a short circuit to a live wire or for open / high resistance. If no fault is detected during circuit testing, then replace the ECM controller.
4. If no fault is found when testing all circuits, replace the fuel level sensor.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
Fuel Level Sensor Reference Voltage Circuit	P2067	-	-	P2066
Fuel level sensor signal circuit	P2067	P2068	P2068	P2066
Fuel Level Sensor Low Reference Circuit	-	P2068	P2068	P2066

• The ignition is on, the engine is running.
• The system voltage is within 9-16 volts.

• The sensor output voltage is less than 0.5 volts.
• The above condition persists for more than 30 seconds.

1. Turn off the ignition, disconnect the harness connector from the fuel level sensor.
2. Turn the ignition on and check with a scan tool if the Fuel Tank Level parameter is less than 4 percent.
• If the value is greater than 4 percent, check the signal circuit for a short to ground. If no fault is found when testing the circuit, replace the ECM.
3. If no fault is found when testing all circuits, replace the fuel level sensor.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
Fuel Level Sensor Reference Voltage Circuit	P2067	-	-	P2066
Fuel level sensor signal circuit	P2067	P2068	P2068	P2066
Fuel Level Sensor Low Reference Circuit	-	P2068	P2068	P2066

• The ignition is on, the engine is running.
• The system voltage is within 9-16 volts.

• The sensor output voltage is more than 3.5 volts.
• The above condition persists for more than 30 seconds.

1. Turn off the ignition, disconnect the harness connector from the fuel level sensor.
2. Check the resistance between the low reference circuit and a known ground, it should be less than 1.0 ohm.
• If greater than 1.0 ohms, then check the low reference voltage circuit for a short circuit to a live wire or for open / high resistance. If no fault is detected during circuit testing, then replace the ECM controller.
3. Turn ignition on, connect a jumper wire with a 3-amp fuse between the signal circuit and the low reference circuit. Verify with a scan tool that the "Fuel Level in Tank" parameter value is greater than 98 percent.
• If the voltage is less than 98 percent, then check the signal circuit for a short circuit to a live wire or for open / high resistance. If no fault is detected during circuit testing, then replace the ECM controller.
4. If no fault is found when testing all circuits, replace the fuel level sensor.

• Check the IMRC solenoid for signs of the valve hitting the intake manifold. This condition may be temperature dependent.
• Inspect the intake manifold length adjustment valve, which should be free of foreign objects or significant contamination.

• The engine is running

• The ECM detects that the IMT sensor voltage is outside the required operating range for more than 4 seconds.

• Check the IMRC solenoid for signs of the valve hitting the intake manifold. This condition may be temperature dependent.

1. Start the engine, quickly press the accelerator pedal from the rest position to the wide-open throttle position and return the pedal to the rest position. Repeat the procedure several times. DTC P2111 should not set.
2. If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.

1. Disconnect the harness connector from the IMT system. Connect a test lamp between the power terminal and the return terminal.
2. Using a scan tool, command the IMT valve on and off. Observe the test lamp, which should illuminate for each change in control circuit state.
• If the test lamp does not light, check the power supply and return circuits for a short to ground or an open/high resistance.
3. If all circuits are normal, then replace the ECM controller.
4. Condition the vehicle for running the DTC. You can also condition the vehicle to run the conditions that were observed based on the recorded malfunction data.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
HO2S signal	P0131, P0137, P2096, P2098	P0134, P0140	P0132, P0138, P2097, P2099	P0133
Low reference voltage	-	P0134, P0140	P0132, P0138, P2097, P2099	P0133

• Signal chain
• Low Voltage Reference Circuit
• Ignition Voltage Circuit 1
• Heater control circuit

• Before the ECM can set DTCs P2096 or P2098, DTCs P0030, P0031, P0032, P0041, P0050, P0051, P0052, P0101, P0131, P0132, P0135, P0137, P0138, P0140, P0141, P0151, P0152, P0155, P0157, P0158, P0160, P0161, P2231, P2234, P2237, P2240, P2243, P2247, P2251, P2254, P2270, P2271, P2273, P2626, and P2629.
• The engine runs for more than 2 seconds.
• Fuel injection correction control based on the measurement results at the catalytic converter outlet is enabled.
• The front and rear HO2S sensors operate in closed loop mode.
• Diagnostic tests for codes P2096 and P2098 run continuously once the above conditions have been met for more than 40 seconds.

• The fuel supply correction based on the results of measurements at the output of the catalytic converter is shifted towards depletion by more than 3 percent of the value of the lambda probe HO2S for more than 4 seconds.

1. With the engine running, monitor the HO2S voltage parameter. This value should fluctuate above and below the range of 350-550 mV.
2. If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.

1. Turn ignition off, disconnect harness connector from appropriate HO2S.
2. Turn on the ignition, check that the HO2S parameter is in the range of 350-500 mV.
• If less than 350 mV, test the HO2S signal circuit for a short to ground. If no fault is found when testing the circuit/connections, replace the ECM.
3. Check for the following faults:
• Lean fuel at the injectors.
• Water penetration into the HO2S harness connector.
• Low pressure in the fuel supply system.
• Fuel contamination.
• Exhaust leak near HO2S sensor.
• HO2S sensor contamination with silicone.
• Engine vacuum leak.
• If any of the above faults are detected, they should be corrected.
4. If no fault is found when testing all circuits/connections, replace the appropriate HO2S sensor.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
HO2S signal	P0131, P0137, P2096, P2098	P0134, P0140	P0132, P0138, P2097, P2099	P0133
Low reference voltage	-	P0134, P0140	P0132, P0138, P2097, P2099	P0133

• Signal chain
• Low Voltage Reference Circuit
• Ignition Voltage Circuit 1
• Heater control circuit

• Before the ECM can set DTCs P2096 or P2098, DTCs P0030, P0031, P0032, P0041, P0050, P0051, P0052, P0101, P0131, P0132, P0135, P0137, P0138, P0140, P0141, P0151, P0152, P0155, P0157, P0158, P0160, P0161, P2231, P2234, P2237, P2240, P2243, P2247, P2251, P2254, P2270, P2271, P2273, P2626, and P2629.
• The engine runs for more than 2 seconds.
• Fuel injection correction control based on the measurement results at the catalytic converter outlet is enabled.
• The front and rear HO2S sensors operate in closed loop mode.
• Diagnostic tests for codes P2097 and P2099 run continuously once the above conditions have been met for more than 40 seconds.

• The fuel injection correction based on the measured results at the catalytic converter outlet is shifted towards enrichment by more than -3 percent from the HO2S lambda probe value for more than 4 seconds.

1. With the engine running, monitor the HO2S voltage parameter. This value should fluctuate above and below the range of 350-550 mV.
2. If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.

1. Turn ignition off, disconnect harness connector from appropriate HO2S.
2. Turn on the ignition, check that the HO2S parameter is in the range of 350-500 mV.
• If less than 350 mV, test the HO2S signal circuit for a short to ground. If no fault is found when testing the circuit/connections, replace the ECM.
3. Check for the following faults:
• The fuel injectors have a rich mixture
• Water penetration into the HO2S harness connector.
• High pressure in the fuel supply system.
• Fuel contamination.
• Fuel saturation of the adsorber of the gasoline vapor recovery system (SUPB)
• Difficulty in exhaust gas release.
• HO2S sensor contamination with silicone
• If any of the above faults are detected, they should be corrected.
4. If no fault is found when testing all circuits/connections, replace the appropriate HO2S sensor.

• The ECM power-off process in the last driving cycle is now complete.
• DTC P2105 runs continuously after the specified condition is met.

• If DTC P2105 is set, the engine will stall and will not restart until the ignition is turned off and then back on.
• Other DTCs are set at the same time as P2105.
• The ignition key cannot be removed from the ignition switch until the next ignition cycle begins.

1. Start the engine, quickly press the accelerator pedal from the rest position to the wide-open throttle position and return the pedal to the rest position. Repeat the procedure several times. DTC P2105 should not set.
2. If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.

1. Turn off the ignition, remove the ECM controller fuse (ECM) or the HFV6 ECM fuse. Check if the fuse is working properly.

Important: This DTC will only set if the fuse is open and the circuits are not grounded. The ignition 1 voltage circuits should be thoroughly tested for an intermittent short to ground.

• If the fuse is open, test both ignition 1 voltage circuits between the fuse and the ECM for an intermittent short to ground.
2. Install the fuse.
3. Disconnect the ECM wiring harness connector. Turn the ignition on, check under load for battery voltage on both ignition 1 voltage circuits at the ECM.
• If voltage is less than B+, repair open/high resistance in ignition 1 voltage circuit.
4. If all circuits and connections are normal, replace the ECM.

• The car's speed is 0 km/h (0 mph).
• Engine speed is less than 40 rpm.
• Engine coolant temperature is between 5-85°C (41-185°F).
• The intake air temperature is between 5-60°C (41-140°F).
• Ignition voltage 1 is greater than 10 volts.
• Accelerator pedal position is less than 15%.
• The ECM performs a closed throttle test with the ignition on and the engine off.
• DTC P2107 runs when the above conditions are met during throttle actuator control system initialization.

1. Turn ignition ON, monitor DTC information with scan tool for 30 seconds. DTC P2107 should not set.
• If DTC P2107 is set, replace the ECM.
2. If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.

• Ignition in the "ON" position.
• The vehicle speed is less than 40 km/h
• The measured intake air temperature is greater than 40°C.

1. Start the engine, quickly press the accelerator pedal from the rest position to the wide-open throttle position and return the pedal to the rest position. Repeat the procedure several times. DTC P2111 should not set.
2. If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.

1. Disconnect the ECM wiring harness connector. Turn on the ignition, check under load for battery voltage on the ignition voltage circuits at the ECM.
• If voltage is less than B+, repair open/high resistance in ignition voltage circuit.
2. If all circuits and connections are normal, replace the ECM.

Chain	Short circuit with "ground"	High resistance	Breakup	Short circuit to live wire	Signal parameters
Accelerator Pedal Position (APP) Sensor 1 5V Reference Circuit	P2122	P2138	P2122	P2123	-
Accelerator Pedal Position (APP) Sensor 2 5V Reference Circuit	P0122, P0222, P2122	P0121, P0221, P2138	P2127	P0123, P0223, P2123	-
Accelerator Pedal Position (APP) Sensor 1 Signal	P2122	P2138	P2122	P2123	P2138
Accelerator Pedal Position (APP) Sensor 2 Signal	P2127	P2138	P2127	P2128	P2138
Accelerator Pedal Position (APP) Sensor 1 Low Reference Circuit	-	-	P2123	-	-
Accelerator Pedal Position (APP) Sensor 1 Low Reference Circuit	-	-	P2128	-	-

• The ignition is on or the engine is running.
• Ignition voltage 1 is greater than 7 volts.
• Diagnostic tests are performed continuously when the above conditions are met.

• The ECM detects that the voltage difference between APP sensors 1 and 2 is greater than 0.21 V.
• The ECM detects that the voltage difference between APP sensors 1 and 2 with the pedal partially depressed is greater than 0.27 V.
• The ECM detects that the voltage difference between APP sensors 1 and 2 with the pedal fully depressed is greater than 1.07 V.
• The ECM detects that the APP sensor 1 voltage is greater than 1.17 V when leaving the idle range and that the voltage difference between APP sensors 1 and 2 is greater than 0.04 V.
• Any of the above conditions occurs for more than 4 seconds.

1. Turn on ignition, monitor APP sensor parameters using a scanning device. Make sure that the voltage of both APP sensors is within 0.4-4.5 V.
2. Quickly depress the accelerator pedal from the rest position to the wide open throttle (WOT) position and release the pedal. Repeat this procedure several times. DTC P2122, P2123, P2127, P2128, or P2138 should not set.
3. Slowly depress the accelerator pedal until the throttle valve is fully open, and then slowly return the pedal to the closed throttle position. Repeat this procedure several times. DTC P2122, P2123, P2127, P2128, or P2138 should not set.
4. If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.

1. Turn off the ignition, disconnect the wiring harness connector from the accelerator pedal assembly.
2. Turn ignition off, check resistance between the appropriate APP sensor low reference circuit and ground; the resistance should be below 5 ohms.
• If resistance is greater than 5 ohms, test the APP sensor low reference circuit for a short to voltage or an open/high resistance. If circuit/connections test normal, replace the ECM.

Important: The 5-volt reference circuits are internally and externally connected to the ECM. Other component DTCs may be set. If other DTCs are set, use the electrical diagram to identify the appropriate circuits and components.

3. Turn ignition on, check voltage between the appropriate 5V reference circuit of the APP sensor and ground; the voltage should be in the range of 4.8-5.2 V.
• If less than 4.8 V, test the APP sensor 5 V reference circuit for a short to ground or an open/high resistance. If the circuit/connections test normal, replace the ECM.
• If the voltage is greater than 5.2 V, check the 5 V reference circuit of the APP sensor for a short circuit to the supply voltage. If no fault is detected during circuit / connection testing, replace the ECM controller.
4. Using a scan tool, check that the voltage parameter of the corresponding APP sensor is less than 0.3 V.
• If the voltage is greater than 0.3 V, test the appropriate APP sensor signal circuit for a short to supply voltage. If the circuit/connections test normal, replace the ECM.
5. Connect a jumper wire with a 3 A fuse between the appropriate signal circuit and the 5 V reference circuit of the APP sensor. Verify that the APP sensor voltage parameter is greater than 4.8 V.
• If less than 4.8 V, test the appropriate APP sensor signal circuit for a short to ground or an open/high resistance. If the circuit/connections test normal, replace the ECM.
• If both APP sensor voltage readings are greater than 4.8 V, test both APP sensor signal circuits for shorts to each other. If no fault is found when testing the circuit/connections, replace the ECM.
6. If all circuits/connections are normal, check or replace the accelerator pedal assembly.

• Engine speed is less than 40 rpm.
• The car's speed is 0 km/h (0 mph).
• Engine coolant temperature (ECT) is between 5-85°C (41-185°F).
• Intake air temperature is greater than 5-60°C (41-140°F).
• The accelerator pedal position sensor signal corresponds to an angle of less than 14.9%.
• Ignition voltage 1 is greater than 10 volts.
• DTC P2176 runs continuously after the above conditions are met for approximately 1 second.

• The ECM detects that the TP sensor 1 voltage is not within 0.2-0.9 V during the idle speed learning procedure.
• The ECM detects that the TP sensor 2 voltage is not between 4.2-4.8 V during the idle speed learning procedure.
• Minimum throttle position is not set during idle speed determination after ECM replacement.
• Any of the above conditions occurs for more than 4 seconds.

1. Turn the ignition switch to ON, quickly press the accelerator pedal from the rest position to the wide open throttle (WOT) position and release the pedal. Repeat the procedure several times. Check the DTC data with a scan tool. Verify that DTCs P0121, P0122, P0123, P0221, P0222, P0223, P0638 or P2101 are not set.
• If one of the above DTCs is set, refer to the corresponding DTC information for further diagnosis.
2. DTC P2176 is an informational diagnostic trouble code. Perform the Idle Parameters Learn Procedure, refer to Idle Parameters Learn Procedure.
• If DTC P2176 resets after performing the idle speed test procedure, replace the throttle body.
3. If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.

• DTCs P0101, P0121, P0122, P0123, P0133, P0153, P0221, P0222, P0223, P0336, P0338, P0443, P0458, P0459, P0461, P0462, P0463, P2066, P2067, and P2068 must pass before the ECM will report DTCs P2177, P2179, P2187, or P2189.
• The fuel system is in a closed loop.
• Long term fuel trim is in effect.
• Engine coolant temperature is greater than 60°C (140°F).
• Intake air temperature is less than 60°C (140°F).
• The fuel vapor recovery system canister purge solenoid valve is not engaged.
• Fuel level is greater than 11.6%.
• Air supply to the engine is more than 7,000 g.
• DTCs P2177, P2179, P2187, and P2189 run continuously after the above conditions have been present for at least 300 seconds.

• This DTC sets when there is a problem with the fuel delivery system. Carefully check all items that cause a lean condition. See "Fuel System Diagnosis".
• Any inadequate air entering the engine will cause this DTC to set. Carefully inspect all areas of the engine for vacuum leaks.
• A problem with the mass flow sensor may cause this DTC to be installed without installing a DTC for the mass flow sensor. If the mass air flow sensor is faulty, the mass air flow sensor parameters will appear normal.
• Check that the correct type of positive crankcase ventilation valve is being used. Check that the correct type of air cleaner is being used. Make sure the fuel filler cap is in place and tightly closed. Make sure the engine oil dipstick is fully inserted.

1. If other DTCs are set in addition to DTC P2177, P2179, P2187, or P2189, refer to the information for those DTCs to diagnose them.
2. The engine is at normal operating temperature, monitor the Total Fuel Trim Avg. parameter with a scan tool. The Total Fuel Trim Avg. parameter should be between -22 and +23%.

1. Read the LT FT Bn 1 and Bn 2 Cruise/Accel parameters to determine if the lean condition is affecting one bank of the engine cylinders or both.
• If leanness affects both banks, check for the following problems:
• Mass air flow sensor zero shift.
• Vacuum leaks in the air intake system after the mass air flow sensor.
• Fuel contamination.
• Cracks, kinks or poor connections in vacuum hoses.
• The fuel system operates in lean mode.
• Vacuum leaks in the intake manifold throttle body.
• Leak in the positive crankcase ventilation system.
• Grounding of the ECM controller for cleanliness, tightness and correct installation.
• For high engine oil levels - A high engine oil level causes an oil deposit to form on the mass air flow sensor (MAF), causing an indication of a poor mixture. The mass Air flow Sensor (MAF) does not need to be replaced.
• If the lean condition occurs on only one bank of engine cylinders, check for the following faults:
• Vacuum leaks affecting only one bank of cylinders - for example, in the intake manifold, in the injector seals.
• The injectors are delivering too lean a mixture.
• Missing, clogged or leaking exhaust system components.
• The reliability of the heated oxygen sensor (HO2S) installation and the absence of contact between the electrical connector and the exhaust system.
• Mechanical engine failure.
2. If everything is normal, see Diagnostic Information.

• DTCs P0101, P0121, P0122, P0123, P0133, P0153, P0221, P0222, P0223, P0336, P0338, P0443, P0458, P0459, P0461, P0462, P0463, P2066, P2067, and P2068 must pass before the ECM will report DTCs P2178, P2180, P2188, or P2190.
• The fuel system is in a closed loop.
• Long term fuel trim is in effect.
• Engine coolant temperature is greater than 60°C (140°F).
• Intake air temperature is less than 60°C (140°F).
• The fuel vapor recovery system canister purge solenoid valve is not engaged.
• Fuel level is greater than 11.6%.
• Air supply to the engine is more than 7,000 g.
• DTCs P2178, P2180, P2188, and P2190 run continuously after the above conditions have been present for at least 300 seconds.

1. If other DTCs are also set, refer to the associated DTC information for further diagnosis.
2. The engine is at normal operating temperature, monitor the Total Fuel Trim Avg. parameter with a scan tool. The Total Fuel Trim Avg. parameter should be between -22 and +23%.

1. Read the LT FT Bn 1 and Bn 2 Cruise/Accel or Idle/Decel parameters to determine if the enrichment is affecting one bank of the engine or both.
• If enrichment affects both rows, check for the following problems:
• Mass air flow sensor zero shift.
• The air intake duct is damaged
• Reduced air filter capacity
• Foreign bodies in the mass air flow sensor.
• Excessive fuel entering the crankcase - change oil if necessary.
• Fuel contamination.
• Grounding of the ECM controller for cleanliness, tightness and correct installation
• Mechanical engine failure.
• If the rich condition occurs on only one bank of engine cylinders, check for the following faults:
• Injectors deliver too rich a mixture.
• Obstruction in the exhaust system.
• Mechanical engine failure.
2. If everything is normal, see Diagnostic Information.

• Ignition voltage within 10-16 volts.
• The engine is running.

• Warm up the engine to operating temperature. With the engine running, monitor the value of the HO2S being tested using a scan tool.
• The HO2S 1 signal value should vary from less than 200 mV to greater than 800 mV and respond to changes in fuel delivery.
• The HO2S 2 signal value should become greater than 200 mV when the throttle position is changed from closed to wide open and then back to closed, quickly performed 3 times after the engine has been running for 30 seconds at 1500 rpm.
• If any HO2S heater fault codes are set, you must first run diagnostics for those codes.
• A faulty HO2S sensor may be caused by contamination. Before replacing the HO2S being tested, check for the following sources of contamination:

1. Disconnect the HO2S sensor being tested.
2. Turn the ignition on, measure the voltage between the low voltage signal circuit terminal of the HO2S sensor being tested and a known ground, which should be approximately 2-40 mV.
• If the voltage is greater than approximately 40 mV, test the low voltage signal circuit of the HO2S being tested for a short to a live wire. If the circuit is normal, replace the controller.
• If the voltage is less than approximately 2 mV, test the low voltage signal circuit of the HO2S being tested for high resistance. If the circuit is normal, replace the controller.
3. Measure the voltage between the high voltage signal circuit terminal of the HO2S under test and a known ground, which should be approximately 450 mV.
• If the voltage is greater than approximately 450 mV, test the high voltage signal circuit of the HO2S being tested for a short to a live wire. If the circuit is normal, replace the controller.
• If the voltage is less than approximately 450 mV, test the high voltage signal circuit of the HO2S being tested for high resistance. If the circuit is normal, replace the controller.
4. Install a 3-amp fusible link jumper wire between the high voltage signal and low voltage signal terminals of the HO2S being tested. A reading of 0 mV should be obtained for the HO2S being tested.
• If the obtained value is not equal to 0 mV, and checking all circuits and connectors did not reveal a malfunction, then replace the controller.
5. Connect a test light between the high voltage terminal of the HO2S being tested and battery voltage. The HO2S being tested should read approximately 1095 mV.
• If the obtained value is not equal to 1095 mV, and checking all circuits and connectors did not reveal a malfunction, then replace the controller.
6. If the controller and all circuits are in good condition, replace the HO2S sensor that was tested.

• Ignition voltage within 10-16 volts.
• The engine is running.

• Warm up the engine to operating temperature. With the engine running, monitor the value of the HO2S being tested using a scan tool.
• The HO2S 1 signal value should vary from less than 200 mV to greater than 800 mV and respond to changes in fuel delivery.
• The HO2S 2 signal value should become greater than 200 mV when the throttle position is changed from closed to wide open and then back to closed, quickly performed 3 times after the engine has been running for 30 seconds at 1500 rpm.
• If any HO2S heater fault codes are set, you must first run diagnostics for those codes.
• A faulty HO2S sensor may be caused by contamination. Before replacing the HO2S being tested, check for the following sources of contamination:

1. Disconnect the HO2S sensor being tested.
2. Turn the ignition on, measure the voltage between the low voltage signal circuit terminal of the HO2S sensor being tested and a known ground, which should be approximately 2-40 mV.
• If the voltage is greater than approximately 40 mV, test the low voltage signal circuit of the HO2S being tested for a short to a live wire. If the circuit is normal, replace the controller.
• If the voltage is less than approximately 2 mV, test the low voltage signal circuit of the HO2S being tested for high resistance. If the circuit is normal, replace the controller.
3. Measure the voltage between the high voltage signal circuit terminal of the HO2S under test and a known ground, which should be approximately 450 mV.
• If the voltage is greater than approximately 450 mV, test the high voltage signal circuit of the HO2S being tested for a short to a live wire. If the circuit is normal, replace the controller.
• If the voltage is less than approximately 450 mV, test the high voltage signal circuit of the HO2S being tested for high resistance. If the circuit is normal, replace the controller.
4. Install a 3-amp fusible link jumper wire between the high voltage signal and low voltage signal terminals of the HO2S being tested. A reading of 0 mV should be obtained for the HO2S being tested.
• If the obtained value is not equal to 0 mV, and checking all circuits and connectors did not reveal a malfunction, then replace the controller.
5. Connect a test light between the high voltage terminal of the HO2S being tested and battery voltage. The HO2S being tested should read approximately 1095 mV.
• If the obtained value is not equal to 1095 mV, and checking all circuits and connectors did not reveal a malfunction, then replace the controller.
6. If the controller and all circuits are in good condition, replace the HO2S sensor that was tested.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
Reference voltage 5V	P2228	P2228	P2229	-
Barometric pressure sensor signal	P2228	P2228	P2229	-
Low reference voltage	P2228 -	P2229	-	-

• Before the ECM will report DTC P2227, DTCs P0121, P0122, P0123, P0221, P0222, P0223, P0335, P0336, P0338, P2228, and P2229 must successfully run.
• The engine runs for more than 20 seconds.
• Mass air flow is greater than 11 g/s.
• The difference between the calculated absolute manifold pressure and the pressure from the barometric pressure sensor is less than 1.0 kPa for more than 3 seconds.
• DTC P2227 runs continuously after the specified conditions are met for 2 seconds.

• The engine is running.
• These DTCs run continuously after the above conditions are present for 2 seconds.

• The ECM detects that the barometric pressure has changed by more than 5 kPa within 20 seconds.
• The ECM detects that the barometric pressure has changed by more than 30 kPa since the last ignition cycle.
• Any of the listed conditions occurs for at least 4 seconds.

• The ECM detects that the BARO sensor signal voltage is less than 0.20 V and the BARO sensor pressure is less than 50 kPa.
• The above condition occurs for more than 4 seconds.

• The ECM detects that the BARO sensor signal voltage is greater than 4.8 V and the BARO sensor pressure is greater than 115 kPa.
• The above condition occurs for more than 4 seconds.

1. Start the engine, read the DTC information with a scan tool. DTC P2227, P2228, or P2229 should not set.
2. If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.

1. Turn on the ignition, monitor the barometric pressure sensor parameter using a scanning device, moving the wiring harness connectors on the barometric pressure sensor and the ECM controller. Make sure that the barometric pressure sensor parameter does not change by more than 3 kPa.
• If the BARO parameter changes more than the specified amount, repair the associated wiring harnesses/connectors.
2. Turn off the ignition, disconnect the harness connector from the barometric pressure sensor.

Important: The barometric pressure sensor signal circuit is pulled up to high voltage through a 1 Mohm resistor.

3. Turn on ignition, monitor the barometric pressure sensor signal voltage using a scanning device. Make sure that the scanning device shows 4.8-5.2 V.
• If the signal is less than 4.8 V, check the signal circuit of the barometric pressure sensor for a short circuit to ground. If no fault is detected during circuit / connection testing, replace the ECM controller.
• If the voltage is greater than 5.2 V, check the barometric pressure sensor signal circuit for a short circuit to the supply voltage. If no fault is detected during circuit / connection testing, replace the ECM controller.
4. Connect the signal circuit of the barometric pressure sensor to the housing of the ECM controller with a jumper with a fuse. Check the voltage parameter of the barometric pressure sensor signal using a scanning device. Make sure that the scanning device shows 0 V.
• If the signal is greater than 0 V, check the barometric pressure sensor signal circuit for breakage/high resistance. If no fault is detected during circuit / connection testing, replace the ECM controller.

Important: The 5-volt reference circuits are internally and externally connected to the ECM. Other component DTCs may be set. If other DTCs are set, use the electrical diagram to identify the appropriate circuits and components.

5. Check voltage between 5V reference circuit of barometric pressure sensor and ground; the voltage should be 4.8-5.2 V.
• If the voltage is less than 4.8 V, check the 5 V reference voltage circuit of the barometric pressure sensor for ground short-circuit or burst/high resistance. If no fault is detected during circuit / connection testing, replace the ECM controller.
• If the voltage is greater than 5.2 V, check the 5 V reference voltage circuit of the barometric pressure sensor for a short circuit to the supply voltage. If no fault is detected during circuit / connection testing, replace the ECM controller.
6. Turn ignition off, remove ECM/TCM fuse from underhood electrical block.

Note: DO NOT use a test lamp to check for continuity. Damage to this control unit may result in increased current.

7. Check the resistance between the low reference circuit of the barometric pressure sensor and ground; the resistance should be less than 5 ohms.
• If the resistance is greater than 5 ohms, check the low reference voltage circuit of the barometric pressure sensor for breakage/high resistance. If no fault is detected during circuit / connection testing, replace the ECM controller.
8. If checking all circuits/connections reveals no faults, replace the barometric pressure sensor.

• Diagnostic trouble codes P0030, P0031, P0032, P0050, P0051, and P0052 are not set.
• HO2S sensor heater control is enabled.

• The HO2S internal signal voltage occurs at the same frequency as the heater circuit.
• HO2S sensor heater control is enabled.
• The resistance of the internal sensing element of the ECM controller exceeds 570 ohms.
• The ECM detects an internal HO2S signal voltage of 1.47 - 1.53 V.
• The HO2S sensor is at operating temperature.

1. Turn on the ignition, monitor the voltage parameter of the corresponding HO2S sensor. The voltage parameter of the HO2S sensor should be less than 1050 mV.
2. If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.

1. Turn ignition off, disconnect harness connector from appropriate HO2S.
2. Turn on the ignition, check that the HO2S parameter is in the range of 350-500 mV.
• If the signal is greater than 500 mV, check the HO2S sensor signal circuit for a short circuit to the heater circuit. If no fault is detected during circuit / connection testing, replace the ECM controller.
3. If no fault is found when testing all circuits/connections, replace the appropriate HO2S sensor.

• Ignition voltage within 10-16 volts.
• The engine operates in closed loop mode.
• The HO2S sensor heater is at operating temperature.
• The ECM commands the lambda value to be maintained greater than 1.03 or less than 0.97.
• The ECM sends a command to cut off the fuel supply during engine braking for more than 3 seconds.
• The ECM periodically commands the lambda value to be maintained rich and then lean by changes greater than 2 percent.

• Warm up the engine to operating temperature. With the engine running, monitor the value of the HO2S being tested using a scan tool.
• The HO2S 1 signal value should vary from less than 200 mV to greater than 800 mV and respond to changes in fuel delivery.
• The HO2S 2 signal value should become greater than 200 mV when the throttle position is changed from closed to wide open and then back to closed, quickly performed 3 times after the engine has been running for 30 seconds at 1500 rpm.
• If any HO2S heater fault codes are set, you must first run diagnostics for those codes.
• A faulty HO2S sensor may be caused by contamination. Before replacing the HO2S being tested, check for the following sources of contamination:

1. Disconnect the HO2S sensor being tested.
2. Turn on the ignition, connect a jumper wire with a 3 A fuse between the reference voltage circuit and the low reference voltage circuit.
• Connect a digital multimeter between the boost current circuit input and a known ground. If the voltage is not 1 volt, check for a short to ground, a short to a live wire, or an open/high resistance. If no fault is found when testing the circuit, replace the ECM.
3. If no fault is found when testing all circuits, replace the HO2S sensor being tested.

• Ignition voltage within 10-16 volts.
• The engine is running.

• Warm up the engine to operating temperature. With the engine running, monitor the value of the HO2S being tested using a scan tool.
• The HO2S 1 signal value should vary from less than 200 mV to greater than 800 mV and respond to changes in fuel delivery.
• The HO2S 2 signal value should become greater than 200 mV when the throttle position is changed from closed to wide open and then back to closed, quickly performed 3 times after the engine has been running for 30 seconds at 1500 rpm.
• If any HO2S heater fault codes are set, you must first run diagnostics for those codes.
• A faulty HO2S sensor may be caused by contamination. Before replacing the HO2S being tested, check for the following sources of contamination:

1. Disconnect the HO2S sensor being tested.
2. Measure the voltage between the reference circuit terminal of the HO2S sensor being tested and a known ground, which should be approximately 450 mV.
• If the voltage is greater than approximately 450 mV, test the reference voltage circuit of the HO2S being tested for a short to voltage. If the circuit is normal, replace the controller.
• If the voltage is less than approximately 450 mV, test the high voltage signal circuit of the HO2S being tested for high resistance. If the circuit is normal, replace the controller.
3. Install a 3-amp fusible link jumper wire between the reference and low signal circuit terminals of the HO2S being tested. A reading of 0 mV should be obtained for the HO2S being tested.
• If the obtained value is not equal to 0 mV, and checking all circuits and connectors did not reveal a malfunction, then replace the controller.
4. Connect a test light between the reference voltage circuit terminal of the HO2S being tested and battery voltage. The HO2S being tested should read approximately 1095 mV.
• If the obtained value is not equal to 1095 mV, and checking all circuits and connectors did not reveal a malfunction, then replace the controller.
5. If the controller and all circuits are in good condition, replace the HO2S sensor that was tested.

• Ignition voltage within 10-16 volts.
• The engine is running.

• Warm up the engine to operating temperature. With the engine running, monitor the value of the HO2S being tested using a scan tool.
• The HO2S 1 signal value should vary from less than 200 mV to greater than 800 mV and respond to changes in fuel delivery.
• The HO2S 2 signal value should become greater than 200 mV when the throttle position is changed from closed to wide open and then back to closed, quickly performed 3 times after the engine has been running for 30 seconds at 1500 rpm.
• If any HO2S heater fault codes are set, you must first run diagnostics for those codes.
• A faulty HO2S sensor may be caused by contamination. Before replacing the HO2S being tested, check for the following sources of contamination.

1. Disconnect the HO2S sensor being tested.
2. Install a 3A fusible link jumper between the low reference signal circuit and the low reference return circuit.
• If voltage is not 1 V, test circuit for short or open/high resistance. If circuit tests normal, replace ECM.
3. If the controller and all circuits are in good condition, replace the HO2S sensor that was tested.

• Diagnostic trouble codes P0036, P0037, P0038, P0056, P0057, P0058, P0137, P0138, P0140, P0141, P0157, P0158, P0160, P0161, P0342, P0343, P0366, P0367, P0368, P0443, P0451, P0452, P0453, P0458, and P0459 are not set.
• The engine is running.
• HO2S sensor 2 is at operating temperature for more than 10 seconds.
• Long term fuel trim is in effect.

• If the ECM controller detects that the HO2S 2 sensor voltage is less than 650 mV for 100 seconds, the ECM controller gives a command to enrich the fuel mixture by up to 30 percent for 10 seconds. This diagnostic fault code is set if the ECM controller detects that the HO2S 2 sensor voltage is still less than 650 mV.
• The engine is running.
• HO2S sensor 2 is at operating temperature for more than 10 seconds.
• Long term fuel trim is in effect.

1. Ignition ON, retrieve DTC information with a scan tool. Verify that DTCs P0137, P0138, P0140, P0157, P0158, or P0160 are not set.
• If one of the above DTCs is set, refer to the corresponding DTC information for further diagnosis.
2. Warm up the engine at over 1200 RPM for 30 seconds while monitoring the HO2S voltage reading. This value should fluctuate above and below the 350-550 mV range.
3. If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.

1. With the engine running, move the appropriate rear HO2S sensor wiring harnesses between the HO2S harness connector and the ECM while monitoring the appropriate HO2S voltage parameter. Verify that the HO2S parameter does not change abruptly when moving the appropriate harnesses.
• If the HO2S parameter changes abruptly when the corresponding harnesses are moved, repair the corresponding circuits.
2. Turn ignition off, disconnect harness connector from appropriate HO2S.
3. Turn on the ignition, check that the HO2S parameter is in the range of 350-500 mV.
• If less than 350 mV, test the HO2S signal circuit for a short to ground. If no fault is found when testing the circuit/connections, replace the ECM.
4. Check for the following faults:
• Lean fuel at the injectors.
• Water penetration into the HO2S harness connector.
• Low pressure in the fuel supply system.
• Fuel contamination.
• Vacuum hoses for integrity, kinks and reliability of connections
• Air intake system after MAF sensor for vacuum leaks
• Exhaust system for leaks
• HO2S sensor contamination with silicone
• Mechanical engine failure.
• If any of the above faults are detected, they should be corrected.
5. If no fault is found when testing all circuits/connections, replace the appropriate HO2S sensor.

• Diagnostic trouble codes P0036, P0037, P0038, P0056, P0057, P0058, P0137, P0138, P0140, P0141, P0157, P0158, P0160, P0161, P0342, P0343, P0366, P0367, P0368, P0443, P0451, P0452, P0453, P0458, and P0459 are not set.
• The engine is running.
• HO2S sensor 2 is at operating temperature for more than 10 seconds.
• Long term fuel trim is in effect.

• If the ECM controller detects that the HO2S 2 sensor voltage is greater than 650 mV for 100 seconds, the ECM controller gives a command to deplete the fuel mixture by up to -7 percent for 10 seconds. If the signal voltage still exceeds 650 volts, the ECM controller checks the HO2S sensor at the next fuel cutoff during engine braking. This diagnostic fault code is set if the ECM controller detects that the HO2S 2 sensor signal voltage exceeds 200 mV after 4 seconds in fuel cut-off mode during engine braking.

1. Ignition ON, retrieve DTC information with a scan tool. Verify that DTCs P0137, P0138, P0140, P0157, P0158, or P0160 are not set.
• If one of the above DTCs is set, refer to the corresponding DTC information for further diagnosis.
2. Warm up the engine at over 1200 RPM for 30 seconds while monitoring the HO2S voltage reading. This value should fluctuate above and below the 350-550 mV range.
3. If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.

1. With the engine running, move the appropriate rear HO2S sensor wiring harnesses between the HO2S harness connector and the ECM while monitoring the appropriate HO2S voltage parameter. Verify that the HO2S parameter does not change abruptly when moving the appropriate harnesses.
• If the HO2S parameter changes abruptly when the corresponding harnesses are moved, repair the corresponding circuits.
2. Turn ignition off, disconnect harness connector from appropriate HO2S.
3. Turn on the ignition, check that the HO2S parameter is in the range of 350-500 mV.
• If the signal is greater than 500 mV, check the signal circuit of the HO2S sensor for a short circuit to the supply voltage. If no fault is detected during circuit / connection testing, replace the ECM controller.
4. Check for the following faults:
• The fuel injectors have a rich mixture
• Water penetration into the HO2S harness connector.
• High pressure in the fuel supply system.
• Fuel contamination.
• The air intake duct is damaged
• Reduced air filter capacity
• Obstructions in the exhaust system
• Excessive amount of fuel in the crankcase
• Mechanical engine failure.
• If any of the above faults are detected, they should be corrected.
5. If no fault is found when testing all circuits/connections, replace the appropriate HO2S sensor.

Chain	Short circuit with "ground"	Open/High Resistance	Short circuit to live wire	Signal parameters
HO2S Signal Bank 1 Sensor 1	P0131	P0130, P0134	P0132	P0130, P0133
HO2S Signal Bank 2 Sensor 1	P0137	P0136, P0140	P0138	P0136, P0139
HO2S Signal Bank 2 Sensor 1	P0151	P0150, P0154	P0152	P0150, P0153
HO2S Signal Bank 2 Sensor 2	P0157	P0156, P0160	P0158	P0156, P0159
Low reference voltage	-	P0130, P0136, P0150, P0156	P0134, P0140, P0154, P0160	-

• Ignition voltage within 10-16 volts.
• The engine is running.
• The front heated oxygen sensors are heated to operating temperature.
• The internal signal voltage of the HO2S sensor in the ECM is less than 4.81 volts.
• The fuel supply was cut off during engine braking 10 times and the adjustment was successful.

1. Engine idling, determine voltage for the corresponding HO2S sensor This value should fluctuate above and below the range of 350-550 mV.
2. If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.

1. Turn ignition off, disconnect harness connector from appropriate HO2S sensor.
2. Turn on the ignition, check that the HO2S parameter is in the range of 350-500 mV.
• If less than 350 mV, check the signal circuit for a short to ground. If no fault is found when testing the circuit/connections, replace the ECM.
• If greater than 500 mV, check the signal circuit for a short to a live wire. If no fault is found when testing the circuit/connections, replace the ECM.
3. Turn ignition off, test for 5 ohms or less between the HO2S low reference circuit and a known ground.
• If resistance is greater than 5 ohms, test the low reference circuit for an open/high resistance. If circuit/connections test normal, replace the ECM.
4. Connect a 3 amp fused jumper wire between the signal circuit and the HO2S low reference circuit and test if the HO2S parameter is less than 60 mV.
• If greater than 60 mV, test signal circuit for open/high resistance. If circuit/connections test normal, replace ECM.
5. If no fault is found when testing all circuits/connections, replace the HO2S sensor.

• Ignition voltage within 10-16 volts.
• The engine operates in closed loop mode.
• The HO2S sensor heater is at operating temperature.
• The ECM commands the lambda value to be maintained greater than 1.03 or less than 0.97.
• The ECM sends a command to cut off the fuel supply during engine braking for more than 3 seconds.
• The ECM periodically commands the lambda value to be maintained rich and then lean by changes greater than 2 percent.

• Warm up the engine to operating temperature. With the engine running, monitor the value of the HO2S being tested using a scan tool.
• The HO2S 1 signal value should vary from less than 200 mV to greater than 800 mV and respond to changes in fuel delivery.
• The HO2S 2 signal value should become greater than 200 mV when the throttle position is changed from closed to wide open and then back to closed, quickly performed 3 times after the engine has been running for 30 seconds at 1500 rpm.
• If any HO2S heater fault codes are set, you must first run diagnostics for those codes.
• A faulty HO2S sensor may be caused by contamination. Before replacing the HO2S being tested, check for the following sources of contamination.

1. Disconnect the HO2S sensor being tested.
2. Turn on the ignition, connect a jumper wire with a 3 A fuse between the reference voltage circuit and the low reference voltage circuit.
• Connect a digital multimeter between the boost current circuit input and a known ground. If the voltage is not 1 volt, check for a short to ground, a short to a live wire, or an open/high resistance. If no fault is found when testing the circuit, replace the ECM.
3. If no fault is found when testing all circuits, replace the HO2S sensor being tested.

Step	Operation	Values	Yes	No
1	Is the diagnostic system check complete?	-	Go to operation 2	Go to the "Checking the diagnostic system" item.
2	Turn off the ignition for 30 seconds. Operate the vehicle under conditions that cause the DTC to appear. Using the scan tool, select the DTC display function. Did DTC U0001 occur during this ignition cycle?	-	Go to operation 3	-
3	Replace the ECM. Is the renovation finished?	-	Go to operation 4	-
4	Using a scan tool, clear the diagnostic trouble codes. Turn off the ignition for 30 seconds. Start the engine. Operate the vehicle under conditions that cause the DTC to appear. Did DTC U0001 occur during this ignition cycle?	-	Go to operation 2	Go to operation 5
5	Using the scan tool, select the DTC display function. Are there any DTCs displayed on the display?	-	Go to the appropriate diagnostic trouble code table.	The system is normal

• The ignition switch is in the on position.

• There is no signal from the corresponding CAN network node
• The "key" message from the gearbox controller unit was not received.
• The ECM detects that invalid information has been received from both the left and right drive wheels

• Diagnostic trouble codes U0101 and U0121 are Type C codes.

• Diagnostic trouble codes U0101 and U0121 are Type C codes.

• This code may be caused by a poor connection on a faulty module.
• A module that is not being supplied with power properly may cause this code to be set.
• If there are multiple modules that are not communicating, the one closest to the diagnostic connector must be selected. Some modules do not have internal protection for certain voltage outputs and may be open to battery positive or ignition source voltage. If the input voltage fuse is open and no short circuit is found in that circuit, verify that none of the module's voltage output circuits are shorted to ground before replacing the module. This diagnostic can be used for any module that must report serial data on the high or low speed GMLAN circuits, provided the vehicle has the option that uses that module.

Step	Operation	Values	Yes	No
1	Have you performed a diagnostic system check?	-	Go to operation 2	Go to the "Checking the diagnostic system" item.
2	Check the following circuits of the module that cannot be contacted for an open or short to ground: Battery Positive Voltage Input Circuits Battery Positive Voltage Output Circuits Ignition Voltage Input Circuits Ignition voltage output circuits Battery positive voltage switching circuits Has the problem been detected and corrected?	-	Go to operation 7	Go to operation 3
3	Turn off the ignition. Check the grounding circuits of the module that cannot be contacted for an open circuit. Has the problem been detected and corrected?	-	Go to operation 7	Go to operation 4
4	Check the high speed GMLAN serial data circuit of the module that cannot communicate for an open. Has the problem been detected and corrected?	-	Go to operation 7	Go to operation 5
5	Inspect the wiring harness connectors of the module with which communication cannot be established for secure connections and tight contacts in the following circuits: Battery Positive Voltage Input Circuits Battery Positive Voltage Output Circuits Ignition Voltage Input Circuits Ignition voltage output circuits Switched battery positive voltage supply circuits Grounding circuits High-speed GMLAN serial data circuits Has the problem been detected and corrected?	-	Go to operation 7	Go to operation 6
6	Replace the module that cannot be contacted. Has the replacement been made?	-	Go to operation 7	-
7	Use a scan tool to clear DTC codes. Turn off the ignition for 30 seconds. Start the engine. Subject the vehicle to the conditions that cause the DTC to set. You can also subject the vehicle to the conditions that were observed from the Freeze Frame/Failure Records. DTC code showed misfire?	-	Go to operation 2	Go to operation 8
8	Check to see if any additional diagnostic trouble codes are set. Are there any DTCs that have not yet been diagnosed?	-	Jump to the appropriate diagnostic trouble code table	The system is normal

• The ignition switch is in the on position.

• The ECM is receiving incorrect data from the TCM regarding the transmission.

• Diagnostic trouble code DTC U0402 is a Type C code.

• Diagnostic trouble code DTC U0402 is a Type C code.

Step	Operation	Values	Yes	No
1	Have you performed a diagnostic system check?	-	Go to operation 2	Go to the "Checking the diagnostic system" item.
2	Turn the ignition switch to the LOCK position. Connect the scanning tool to the diagnostic connector. Turn the ignition key to the ON position. Observe DTC data with a scan tool. Are there any other DTCs displayed besides U0442?	-	Jump to the appropriate diagnostic trouble code table	Go to operation 3
3	Use a scan tool to clear the DTC data. Turn off the ignition for at least 30 seconds. Start the engine and let it idle. Did DTC U0402 occur during this ignition cycle?	-	Go to operation 7	See Intermittent Faults
4	Were any other TCM related DTCs or other "U" DTCs set?	-	Jump to the appropriate diagnostic trouble code table	Go to operation 5
5	Check the LAN circuits in the wiring harness between the TCM and the ECM for high resistance or poor connections at the module connectors. Has the problem been detected and corrected?	-	Go to operation 7	Go to operation 6
6	Replace the ECM. Has the replacement been made?	-	Go to operation 7	-
7	Use a scan tool to clear DTC codes. Turn off the ignition for 30 seconds. Start the engine. Subject the vehicle to the conditions that cause the DTC to set. You can also subject the vehicle to the conditions that were observed from the Freeze Frame/Failure Records. DTC code showed misfire?	-	Go to operation 2	Go to operation 8
8	Check to see if any additional diagnostic trouble codes are set. Are there any diagnostic trouble codes displayed that have not been diagnosed?	-	Jump to the appropriate diagnostic trouble code table	The system is normal

(The original text can be found on the website CHEVYMAN.ru)