The wheel speed sensor produces an AC signal whose amplitude and frequency vary with wheel speed. Brake controller (EBCM) uses the frequency of the AC signal to calculate wheel speed.
The following trouble codes are processed in this diagnostic procedure:
- DTC C0035 - Front Left Wheel Speed Sensor Circuit Malfunction
- DTC C0040 - Front Right Wheel Speed Sensor Circuit
- DTC C0045 - Rear Left Wheel Speed Sensor Circuit
- DTC C0050 - Rear Right Wheel Speed Sensor Circuit
C0035, C0040, C0045, C0050
Ignition to the ON position.
C0035, C0040, C0045, C0050
One of the following conditions exists for 0.02 seconds:
- The DTC will set if one wheel speed is 0 while the other wheel speed is above 40 km/h (25 mph).
- There is a short to voltage in the wheel speed sensor (WSS) in one of the WSS sensor circuits
- There is an open in the signal circuit of the WSS sensor.
- Short to Ground - The WSS signal circuit is shorted to ground.
If the appropriate hardware is installed, the following actions occur:
- Brake controller (EBCM) disables ABS and TCS during the ignition cycle.
- The DTC will be set.
- The ABS warning lamp will come on.
- The TCS switch LED will turn off.
- The condition causing the DTC no longer exists.
- Clear DTCs with a scan tool.
- Brake controller (EBCM) automatically clears the DTC history if the current DTC has not been detected in the next 100 cycles.
C0035, C0040, C0045, C0050
In case the customer reports that the ABS indicator is only on during wet weather conditions (rain, snow, car wash, etc.) inspect the WSS sensor wiring for signs of water intrusion. If no DTC is currently set, clear all DTCs and simulate the effect of water ingress by doing the following:
- Spray the area to be tested with a 5% salt solution. In order to get a 5% salt solution, you need to dissolve 2 teaspoons of salt in 354 ml (12 oz) water.
- Carry out a test run of the car on different types of road surfaces (with bumps, turns, etc.) at speeds over 40 km/h (25 mph) for at least 30 seconds.
- If the DTC reappears, replace the suspect WSS sensor or WSS sensor wiring.
- Rinse the area thoroughly with water after finishing work.
The item numbers below are the step numbers in the diagnostic table.
- This step checks for the correct resistance value of the WSS sensor.
- This step checks for the correct voltage being produced by the WSS sensor.
Step | Operation | Values | Yes | No |
1 |
Has the Vehicle Diagnosis Circuit Test already been performed?
|
-
|
Go to step 2
|
Go to item Checking the diagnostic circuitin this section.
|
2 |
Does the scan tool indicate that a DTC is set for this wheel?
|
64 km/h (40 mph)
|
Go to step 3
|
Go to Diagnostic Guide Step 3
|
3 |
Is the measured resistance within the specified range?
|
? over 1M ohm
|
Go to step 4
|
Go to step 8
|
4 |
Important: Do not insert the oscilloscope needle into the pins of the wheel speed sensor connector to measure voltage, as this may damage the pins or case. Is the voltage constantly rising and falling according to the values?
|
0.525 V (down) 1.05 V (up)
|
Go to step 5
|
Go to step 8
|
5 |
Check for a loose connection at the WSS sensor harness connector.
Was the fault condition found and corrected?
|
-
|
Go to step 10
|
Go to step 6
|
6 |
Was the fault condition found and corrected?
|
-
|
Go to step 10
|
Go to step 7
|
7 |
Check for a loose connection at the brake controller harness connector (EBCM).
Was the fault condition found and corrected?
|
-
|
Go to step 10
|
Go to step 9
|
8 |
Replace wheel speed sensor.
Is the replacement completed?
|
-
|
Go to step 10
|
-
|
9 |
Replace EBCM.
Is the replacement complete?
|
-
|
Go to step 10
|
-
|
10 |
Does the DTC clear?
|
-
|
Go to step 2
|
System OK
|
The pump motor is an integral part of the brake pressure modulator valve (BPMV), and the pump motor relay is an integral part of the brake system controller (EBCM). The pump motor relay is disabled during normal system operation. If ABS or traction control is required (TCS), the EBCM turns on the pump motor relay and the pump motor is powered by the battery.
This diagnostic procedure resolves the following DTC:
DTC C0110 Pump Motor Circuit
- The ignition switch is in the ON position.
- Initialization completed.
- The pump motor voltage is not present for 100 milliseconds after the pump motor relay is turned on.
- Pump motor voltage is present for more than 1 second without switching on the pump motor relay for 5 seconds.
If the appropriate hardware is installed, the following actions occur:
- Brake controller (EBCM) disables ABS, TCS and dynamic brake force distribution on the rear wheels (DRP) during the ignition cycle.
- The DTC will be set.
- The ABS warning lamp will come on.
- The condition causing the DTC no longer exists.
- Clear DTCs with a scan tool.
- Brake controller (EBCM) automatically clears the DTC history if the current DTC has not been detected in the next 100 cycles.
- It is important to conduct a thorough inspection of the wires and connectors. A quick and cursory inspection of wires and connectors can lead to a misdiagnosis, which in turn will lead to replacement of parts with the subsequent return of the malfunction.
- Carefully inspect all circuits that may cause malfunctions due to the presence of the following conditions:
- The following conditions can cause an intermittent malfunction:
embossed contacts
Wrong connection
Broken latches
Incorrect connection or damaged contacts
Weak wire connections to contacts
Physical damage to the wiring harness
Weak connection
Frayed wire insulation
Broken wire inside insulation
The item number below is the step number in the diagnostic table.
- This step tests the EBCM pump motor circuits for a short to the BPMV housing.
Step | Operation | Values | Yes | No |
1 |
Have you already performed a Diagnostic System Check on your vehicle?
|
-
|
Go to step 2
|
Go to item Checking the diagnostic circuitin this section.
|
2 |
Was the fault condition found and corrected?
|
-
|
Go to step 8
|
Go to step 3
|
3 |
Is the voltage within the required range?
|
5 ohm
|
Go to step 4
|
Go to step 5
|
4 |
Check the tightness of the connections on the pump motor connector of the valve of the pressure modulator in the brake system (BPMV).
Was the fault condition found and corrected?
|
-
|
Go to step 8
|
Go to step 6
|
5 |
Check for loose connections at the brake controller harness connector (EBCM).
Was the fault condition found and corrected?
|
-
|
Go to step 8
|
Go to step 7
|
6 |
Replace BPMV.
Is the renovation complete?
|
-
|
Go to step 8
|
-
|
7 |
Replace EBCM.
Is the renovation complete?
|
-
|
Go to step 8
|
-
|
8 |
Does the DTC clear?
|
-
|
Go to step 2
|
System OK
|
Brake controller (EBCM) monitors and evaluates the output signal from the hydraulic modulator pressure sensor to determine the brake fluid pressure applied to each wheel. This allows the brake controller (EBCM) determine the rate of force applied to the brake pedal.
DTC Descriptor - Anti-Lock Braking System ABS / Traction Control System Operating Circuit (TCS)
This diagnostic procedure addresses DTC C0131.
The working circuit of the anti-lock braking system (ABS) / traction control (TCS)
Checked during initialization sequence with brake controller self-test (EBCM).
If the brake controller (EBCM) detects a fault in the hydraulic modulator pressure sensor output voltage.
- Brake controller (EBCM) disables the ABS-TCS/ESP systems for the duration of the ignition cycle.
- In this case, one or more warning indicators may light up:
ABS-TCS warning indicator,
ABS-TCS warning badge,
ESP warning icon,
Brake failure indicator, and/or
Trac-off warning icon.
- The current DTC is moved to the DTC history if during the current brake controller self-test (EBCM) no trouble codes were set.
- Use Tech 2 to clear the DTC.
The following item numbers are step numbers in the diagnostic table:
- Check for the fault that is currently triggering the current DTC.
- Checking the integrity of the internal circuits of the brake system controller (EBCM). Internal malfunction in the brake system controller (EBCM) can cause this DTC to appear.
Step | Operation | Values | Yes | No |
1 |
Has a diagnostic check been run on the system?
|
-
|
Go to step 2
|
Go to item Checking the diagnostic circuitin this section.
|
2 |
Is DTC C0131 causing this ignition cycle to fail?
|
-
|
Go to step 3
|
Go to step 4
|
3 |
Are DTCs C0550 or C0551 also set?
|
-
|
Go to item DTC C0550 and C0551in this section.
|
Go to step 4
|
4 |
Have any problems been found and fixed?
|
-
|
Go to step 7
|
Go to step 5
|
5 |
Check the tightness of the connections on the connector of the brake system controller (EBCM).
Have any problems been found and fixed?
|
-
|
Go to step 7
|
Go to step 6
|
6 |
Replace hydraulic modulator. See Brake modulator assembly in this section.
Has the renovation been completed?
|
-
|
Go to step 7
|
Go to step 6
|
7 |
Is DTC C0131 causing this ignition cycle to fail?
|
-
|
Go to step 2
|
Go to step 8
|
8 |
Does the scan tool show any DTC?
|
-
|
Refer to appropriate table for troubleshooting DTCs
|
System OK
|
The normally open stop lamp switch provides battery power to the ECM when the brake pedal is depressed. The ECM sends a serial information message generated when the brake pedal is depressed to the electronic and traction control module (EBTCM) and transmission controller.
This diagnostic procedure works on the following DTC
DTC C0161 ABS/TCS Brake Switch Circuit.
Ignition key to the ON position.
- Brake controller (EBCM) detects an open in the brake signal circuit.
- Both stop lamps are defective.
If the appropriate hardware is installed, the following actions occur:
- The DTC will be set.
- Brake controller (EBCM) stores this information - only the DTC for the duration of the condition.
- Anti-lock braking system (ABS) remains functional.
- ABS indicator stays off (OFF).
- The condition causing the DTC no longer exists.
- Clear DTCs with a scan tool.
- Brake controller (EBCM) automatically clears the DTC history if the current DTC has not been detected in the next 100 cycles.
- It is important to conduct a thorough inspection of the wires and connectors. A quick and cursory inspection of wires and connectors can lead to a misdiagnosis, which in turn will lead to replacement of parts with the subsequent return of the malfunction.
- Carefully inspect all circuits that may cause malfunctions due to the presence of the following conditions:
- Possible causes for this DTC to set are:
embossed contacts
Wrong connection
Broken latches
Incorrect connection or damaged contacts
Weak wire connections to contacts
Physical damage to the wiring harness
Break in the signal circuit of the stop lamp switch.
Stop light switch out of adjustment.
Verify the operation of the stop lamp switch using the scan tool data list. When the brake is pressed, the data list will display the stop lamp switch in the ON position for 2.54 cm (1 inch) way.
Break in the circuits of all stop lamps.
Break in the ground of all stop lamps.
The circuit has wiring problems, contact corrosion, or loose connections.
There is a loose or rusty brake controller ground connection (EBCM).
The item numbers below are the step numbers in the diagnostic table.
- This DTC detects an open in the stop lamp switch signal circuit from the stop lamp point at the splice assembly to the brake system controller (EBCM).
- Brake controller (EBCM) Provides 5 volts to the brake light signal circuit. This small voltage has a ground circuit in the stop lamps. This DTC is set if an open ground circuit occurs.
Step | Operation | Values | Yes | No |
1 |
Have you already performed a Diagnostic System Check on your vehicle?
|
-
|
Go to step 2
|
Go to item Checking the diagnostic circuitin this section.
|
2 |
Does the brake switch status parameter indicate that the lamp is on?
|
-
|
Go to step 4
|
Go to step 3
|
3 |
Test the stop lamp switch signal circuit for an open.
Was the fault condition found and corrected?
|
-
|
Go to step 9
|
Go to step 7
|
4 |
Press the brake pedal.
Are all brake lights off?
|
-
|
Go to step 5
|
See Troubleshooting Guide
|
5 |
Test the brake light supply circuit for an open or high resistance.
Was the fault condition found and corrected?
|
-
|
Go to step 9
|
Go to step 6
|
6 |
Test the stop lamp ground circuit for an open or high resistance.
Was the fault condition found and corrected?
|
-
|
Go to step 9
|
See Troubleshooting Guide
|
7 |
Check the tightness of the connections on the connector of the brake system controller (EBCM).
Was the fault condition found and corrected?
|
-
|
Go to step 9
|
Go to step 8
|
8 |
Replace EBCM.
Is the renovation complete?
|
-
|
Go to step 9
|
-
|
9 |
Does the DTC clear?
|
-
|
Go to step 2
|
System OK
|
Brake controller (EBCM) Provides 5V to the yaw sensor base voltage circuit and ground through the yaw sensor low base voltage circuit, which is also used by the steering angle sensor. Brake controller (EBCM), the yaw sensor assembly and the steering angle sensor share the same 12V power circuit.
The lateral accelerometer sensor provides an output voltage that corresponds to the lateral component of the vehicle's acceleration.
This diagnostic works for DTC C0186 - Lateral Accelerometer Circuit.
The ignition switch is in the ON position.
- If the brake controller (EBCM) detects a fault in the lateral acceleration output voltage.
- Both stop lamps are defective.
- Brake controller (EBCM) disables the ESP system for the duration of the ignition cycle.
- The ABS warning light, ABS warning icon and Trac-off icon come on.
- The condition causing the DTC no longer exists.
- Clear DTCs with a scan tool.
- Brake controller (EBCM) automatically clears the DTC history if the current DTC has not been detected in the next 100 cycles.
The following item numbers are step numbers in the diagnostic table:
- Check for the fault that is currently triggering the current DTC.
Step | Operation | Values | Yes | No |
1 |
Has a diagnostic check been run on the system?
|
-
|
Go to step 2
|
Go to item Checking the diagnostic circuitin this section.
|
2 |
Is DTC C0186 causing this ignition cycle to fail?
|
-
|
Go to step 3
|
Go to step 4
|
3 |
Test the yaw rate sensor 12V ignition common circuit for high resistance, an open circuit, or a short to ground.
Note: The yaw sensor assembly uses a 12V ignition circuit along with the brake controller (EBCM) and angle sensor. A malfunction in the 12V ignition circuit can set DTCs for components that also operate on that circuit. Have any problems been found and fixed?
|
-
|
Go to step 13
|
Go to step 4
|
4 |
Test the common ground circuit of the yaw rate sensor assembly for high resistance or an open circuit.
Note: The yaw sensor assembly shares a reference ground circuit with the steering angle sensor. A malfunction in the reference ground circuit can cause DTCs to be set for the wheel angle sensor. Have any problems been found and fixed?
|
-
|
Go to step 13
|
Go to step 5
|
5 |
Does the meter show 4.8 - 5.2 V?
|
-
|
Go to step 7
|
Go to step 6
|
6 |
Test the stop lamp ground circuit for an open or high resistance.
Have any problems been found and fixed?
|
-
|
Go to step 13
|
Go to step 11
|
7 |
Test the longitudinal acceleration sensor signal circuit for a short to ground, a short to voltage, high resistance, or an open circuit.
Have any problems been found and fixed?
|
-
|
Go to step 13
|
Go to step 8
|
8 |
Test the self-test circuit of the yaw rate sensor assembly for a short to ground, a short to voltage, high resistance, or an open circuit.
Have any problems been found and fixed?
|
-
|
Go to step 13
|
Go to step 9
|
9 |
Check for a loose connection at the yaw rate sensor connector.
Have any problems been found and fixed?
|
-
|
Go to step 13
|
Go to step 10
|
10 |
Replace the yaw rate sensor. See Yaw rate sensorin this section.
Has the renovation been completed?
|
-
|
Go to step 13
|
-
|
11 |
Check the tightness of the connections on the connector of the brake system controller (EBCM).
Have any problems been found and fixed?
|
-
|
Go to step 13
|
Go to step 12
|
12 |
Replace brake controller (EBCM). Cm Brake controllerin this section.
Has the renovation been completed?
|
-
|
Go to step 13
|
-
|
13 |
Is DTC C0186 causing this ignition cycle to fail?
|
-
|
Go to step 2
|
Go to step 14
|
14 |
Use a scan tool to select the DTC display function.
Does the scan tool show any DTC?
|
-
|
Refer to appropriate table for troubleshooting DTCs
|
System OK
|
Brake controller (EBCM) Provides 5 volts to the base circuit of the yaw sensor assembly and ground through the low base voltage circuit of the yaw sensor, which is also used by the steering angle sensor. Brake controller (EBCM), the yaw sensor assembly and the steering angle sensor share the same 12V power circuit.
The yaw sensor provides an output voltage that corresponds to the rotation of the vehicle around its vertical axis.
This diagnostic works for DTC C0196 - Yaw Sensor Circuit.
The ignition switch is in the ON position.
If the brake controller (EBCM) detects a fault in the yaw rate sensor output voltage.
- Brake controller (EBCM) disables the ESP system for the duration of the ignition cycle.
- The ABS warning light, ABS warning icon and Trac-off icon come on.
- The condition causing the DTC no longer exists.
- Clear DTCs with a scan tool.
- Brake controller (EBCM) automatically clears the DTC history if the current DTC has not been detected in the next 100 cycles.
The following item numbers are step numbers in the diagnostic table:
- Check for the fault that is currently triggering the current DTC.
Step | Operation | Values | Yes | No |
1 |
Has a diagnostic check been run on the system?
|
-
|
Go to step 2
|
Go to item Checking the diagnostic circuitin this section.
|
2 |
Is DTC C0196 causing this ignition cycle to fail?
|
-
|
Go to step 3
|
Go to step 4
|
3 |
Test the 12V ignition common circuit of the yaw rate sensor assembly for high resistance, an open circuit, or a short to ground.
Note: The yaw sensor assembly uses a 12V ignition circuit along with the brake controller (EBCM) and angle sensor. A malfunction in the 12V ignition circuit can set DTCs for components that also operate on that circuit. Have any problems been found and fixed?
|
-
|
Go to step 13
|
Go to step 4
|
4 |
Test the common ground circuit of the yaw rate sensor assembly for high resistance or an open circuit.
Note: The yaw rate sensor assembly shares a reference ground circuit with the steering angle sensor. A malfunction in the reference ground circuit can cause DTCs to be set for the wheel angle sensor. Have any problems been found and fixed?
|
-
|
Go to step 13
|
Go to step 5
|
5 |
Does the meter show 4.8 - 5.2 V?
|
-
|
Go to step 7
|
Go to step 6
|
6 |
Test the 5V base voltage circuit of the yaw rate sensor for a short to voltage, high resistance, or an open circuit.
Have any problems been found and fixed?
|
-
|
Go to step 13
|
Go to step 11
|
7 |
Test the yaw rate sensor signal circuit for a short to ground, a short to voltage, high resistance, or an open circuit.
Have any problems been found and fixed?
|
-
|
Go to step 13
|
Go to step 8
|
8 |
Test the self-test circuit of the yaw rate sensor assembly for a short to ground, a short to voltage, high resistance, or an open circuit.
Have any problems been found and fixed?
|
-
|
Go to step 13
|
Go to step 9
|
9 |
Check for a loose connection at the yaw rate sensor connector.
Have any problems been found and fixed?
|
-
|
Go to step 13
|
Go to step 10
|
10 |
Replace the yaw rate sensor assembly. See Yaw rate sensorin this section.
Has the renovation been completed?
|
-
|
Go to step 13
|
-
|
11 |
Check the tightness of the connections on the connector of the brake system controller (EBCM).
Have any problems been found and fixed?
|
-
|
Go to step 13
|
Go to step 12
|
12 |
Replace brake controller (EBCM). Cm Brake controllerin this section.
Has the renovation been completed?
|
-
|
Go to step 13
|
-
|
13 |
Is DTC C0196 causing this ignition cycle to fail?
|
-
|
Go to step 2
|
Go to step 14
|
14 |
Use a scan tool to select the DTC display function.
Does the scan tool show any DTC?
|
-
|
Refer to appropriate table for troubleshooting DTCs
|
System OK
|
Brake controller (EBCM) Provides ground to the low base voltage circuit of the wheel speed sensor. The wheel speed sensor together with the ring counter form an AC signal voltage. The amplitude and frequency of the generated signal are proportional to the wheel speed. Brake controller (EBCM) monitors the wheel speed sensor signal voltage to determine the rotation speed of each wheel and to calculate the characteristic speed of the vehicle.
Brake controller (EBCM) compensates for deviations during continuous rotational speed of the wheel under normal conditions, if the deviations do not exceed the specified parameters. These deviations can be caused by factors such as varying degrees of tire wear or differences in tire pressure between different wheels.
This diagnostic works for DTC C0252 - Vehicle Stability Enhancement System (VSES). The sensors are uncorrelated.
Brake controller (EBCM) receives the output signal from the wheel speed sensor.
If the deviation in wheel speed between different wheels is outside the limits set by the brake controller (EBCM).
- Brake controller (EBCM) disables the ESP system for the duration of the ignition cycle.
- The ABS warning light, ABS warning icon and Trac-off icon come on.
- The condition causing the DTC no longer exists.
- Clear DTCs with a scan tool.
- Brake controller (EBCM) automatically clears the DTC history if the current DTC has not been detected in the next 100 cycles.
The following item numbers are step numbers in the diagnostic table:
- Check for the fault that is currently triggering the current DTC.
- Check the wheel speed sensor for a problem.
- Check the wheel speed sensor ring counter for a malfunction.
Step | Operation | Values | Yes | No |
1 |
Has a diagnostic check been run on the system?
|
-
|
Go to step 2
|
Go to item Checking the diagnostic circuitin this section.
|
2 |
Is DTC C0252 causing this ignition cycle to fail?
|
-
|
Go to step 3
|
Go to step 4
|
3 |
Is DTC C0035, C0040, C0045, or C0050 also causing this ignition cycle to fail?
|
-
|
Go to item DTC C0035, C0040, C0045, C0050.
|
Go to step 4
|
4 |
Inspect tires for incorrect tire size, incorrect tire pressure, or other problem that may be causing incorrect wheel speed readings.
Have any problems been found and fixed?
|
-
|
Go to step 9
|
Go to step 5
|
5 |
Have any problems been found and fixed?
|
-
|
Go to step 9
|
Go to step 6
|
6 |
Note: If there is no oscilloscope, perform an external inspection in the following scope:
Have any problems been found and fixed?
|
-
|
Go to step 9
|
Go to step 7
|
7 |
Check the tightness of the connections on the connector of the brake system controller (EBCM).
Have any problems been found and fixed?
|
-
|
Go to step 9
|
Go to step 8
|
8 |
Replace EBCM.
Has the renovation been completed?
|
-
|
Go to step 9
|
-
|
9 |
Is any speed sensor output DTC causing this ignition cycle to fail?
|
-
|
Go to step 2
|
Go to step 10
|
10 |
Use a scan tool to select the DTC display function.
Does the scan tool show any DTC?
|
-
|
Refer to appropriate table for troubleshooting DTCs
|
System OK
|
Internal fault detection occurs within the controller. No external circuits are involved in this process.
This diagnostic procedure resolves the following DTC:
DTC C0280 Stability Enhancement System Runs Too Long
The microprocessor runs an internal error detection program when a power-on command is received. All that is required is voltage and ground. This program works even when the voltage is out of the allowed operating range.
- The controller detects an internal write error.
- The controller detects an internal checksum error.
If the appropriate hardware is installed, the following actions can occur with the controller:
- The ABS warning lamp lights up.
- The brake warning light comes on.
- The traction control LED goes out (TCS).
- The ESP operation indicator lamp flashes for 15 seconds or more.
- The condition causing the DTC no longer exists.
- Clear DTCs with a scan tool.
- Brake controller (EBCM) automatically clears the DTC history if the current DTC has not been detected in the next 100 cycles.
- This DTC can be stored as a history DTC without affecting the performance of the controller. If the code is only stored as a history DTC, and is not restored as a valid DTC, there is no need to replace the controller.
- If this DTC recovers both as a history and a valid DTC, the controller needs to be replaced.
Step | Operation | Values | Yes | No |
1 |
Have you already performed a Diagnostic System Check on your vehicle?
|
-
|
Go to step 2
|
Go to item Checking the diagnostic circuitin this section.
|
2 |
DTC recovered as current DTC?
|
-
|
Go to step 3
|
Go to step 4
|
3 |
Replace the controller, setting the fault code as the current code.
Is the replacement completed?
|
-
|
Go to step 4
|
-
|
4 |
Does the DTC clear?
|
-
|
Go to step 2
|
System OK
|
Brake controller (EBCM) Provides 5 volts to the base circuit of the yaw sensor assembly and ground through the low base voltage circuit of the yaw sensor, which is also used by the steering angle sensor. Brake controller (EBCM), the yaw rate sensor assembly and the steering angle sensor share the same 12V power circuit.
This diagnostic works for DTC C0287 - Longitudinal Accelerometer Circuit.
The ignition switch is in the ON position.
If the brake controller (EBCM) detects a fault in the yaw rate sensor output voltage.
- Brake controller (EBCM) disables the ESP system for the duration of the ignition cycle.
- The ABS warning light, ABS warning icon and Trac-off icon come on.
- The condition causing the DTC no longer exists.
- Clear DTCs with a scan tool.
- Brake controller (EBCM) automatically clears the DTC history if the current DTC has not been detected in the next 100 cycles.
The following item numbers are step numbers in the diagnostic table:
- Check for the fault that is currently triggering the current DTC.
Step | Operation | Values | Yes | No |
1 |
Has a diagnostic check been run on the system?
|
-
|
Go to step 2
|
Go to item Checking the diagnostic circuitin this section.
|
2 |
Is DTC C0287 causing this ignition cycle to fail?
|
-
|
Go to step 3
|
Go to step 4
|
3 |
Test the 12V ignition common circuit of the yaw rate sensor assembly for high resistance, an open circuit, or a short to ground.
Note: The yaw sensor assembly uses a 12V ignition circuit along with the brake controller (EBCM) and angle sensor. A malfunction in the 12V ignition circuit can set DTCs for components that also operate on that circuit. Have any problems been found and fixed?
|
-
|
Go to step 13
|
Go to step 4
|
4 |
Test the common ground circuit of the yaw rate sensor assembly for high resistance or an open circuit.
Note: The yaw rate sensor assembly shares a reference ground circuit with the steering angle sensor. A malfunction in the reference ground circuit can cause DTCs to be set for the wheel angle sensor. Have any problems been found and fixed?
|
-
|
Go to step 13
|
Go to step 5
|
5 |
Does the meter show 4.8 - 5.2 V?
|
-
|
Go to step 7
|
Go to step 6
|
6 |
Test the 5V base voltage circuit of the yaw rate sensor for a short to voltage, high resistance, or an open circuit.
Have any problems been found and fixed?
|
-
|
Go to step 13
|
Go to step 11
|
7 |
Test the yaw rate sensor signal circuit for a short to ground, a short to voltage, high resistance, or an open circuit.
Have any problems been found and fixed?
|
-
|
Go to step 13
|
Go to step 8
|
8 |
Test the self-test circuit of the yaw rate sensor assembly for a short to ground, a short to voltage, high resistance, or an open circuit.
Have any problems been found and fixed?
|
-
|
Go to step 13
|
Go to step 9
|
9 |
Check for a loose connection at the yaw rate sensor connector.
Have any problems been found and fixed?
|
-
|
Go to step 13
|
Go to step 10
|
10 |
Replace the yaw rate sensor assembly. See Yaw rate sensorin this section.
Has the renovation been completed?
|
-
|
Go to step 13
|
-
|
11 |
Check the tightness of the connections on the connector of the brake system controller (EBCM).
Have any problems been found and fixed?
|
-
|
Go to step 13
|
Go to step 12
|
12 |
Replace brake controller (EBCM). Cm Brake controllerin this section.
Has the renovation been completed?
|
-
|
Go to step 13
|
-
|
13 |
Is DTC C0196 causing this ignition cycle to fail?
|
-
|
Go to step 2
|
Go to step 14
|
14 |
Use a scan tool to select the DTC display function.
Does the scan tool show any DTC?
|
-
|
Refer to appropriate table for troubleshooting DTCs
|
System OK
|
Brake controller (EBCM) Provides 5 volts to the base circuit of the yaw sensor assembly and ground through the low base voltage circuit of the yaw sensor, which is also used by the steering angle sensor. Brake controller (EBCM), the yaw sensor assembly and the steering angle sensor share the same 12V power circuit.
The yaw sensor provides an output voltage that corresponds to the rotation of the vehicle around its vertical axis.
This diagnostic procedure addresses DTC C0292.
VSES (Vehicle Stability Enhancement System) instrument cluster sensor circuit VSES.
The ignition switch is in the ON position.
If the brake controller (EBCM) detects a fault in the yaw rate sensor output voltage.
- Brake controller (EBCM) disables the ESP system for the duration of the ignition cycle.
- The ABS warning light, ABS warning icon and Trac-off icon come on.
- The condition causing the DTC no longer exists.
- Clear DTCs with a scan tool.
- Brake controller (EBCM) automatically clears the DTC history if the current DTC has not been detected in the next 100 cycles.
The following item numbers are step numbers in the diagnostic table:
- Check for the fault that is currently triggering the current DTC.
Step | Operation | Values | Yes | No |
1 |
Has a diagnostic check been run on the system?
|
-
|
Go to step 2
|
Go to item Checking the diagnostic circuitin this section.
|
2 |
Is DTC C0292 causing this ignition cycle to fail?
|
-
|
Go to step 3
|
Go to step 4
|
3 |
Test the 12V ignition common circuit of the yaw rate sensor assembly for high resistance, an open circuit, or a short to ground.
Note: The yaw sensor assembly uses a 12V ignition circuit along with the brake controller (EBCM) and angle sensor. A malfunction in the 12V ignition circuit can set DTCs for components that also operate on that circuit. Have any problems been found and fixed?
|
-
|
Go to step 13
|
Go to step 4
|
4 |
Test the common ground circuit of the yaw rate sensor assembly for high resistance or an open circuit.
Note: The yaw rate sensor assembly shares a reference ground circuit with the steering angle sensor. A malfunction in the reference ground circuit can cause DTCs to be set for the wheel angle sensor. Have any problems been found and fixed?
|
-
|
Go to step 13
|
Go to step 5
|
5 |
Does the meter show 4.8 - 5.2 V?
|
-
|
Go to step 7
|
Go to step 6
|
6 |
Test the 5V base voltage circuit of the yaw rate sensor for a short to voltage, high resistance, or an open circuit.
Have any problems been found and fixed?
|
-
|
Go to step 13
|
Go to step 11
|
7 |
Test the yaw rate sensor signal circuit for a short to ground, a short to voltage, high resistance, or an open circuit.
Have any problems been found and fixed?
|
-
|
Go to step 13
|
Go to step 8
|
8 |
Test the self-test circuit of the yaw rate sensor assembly for a short to ground, a short to voltage, high resistance, or an open circuit.
Have any problems been found and fixed?
|
-
|
Go to step 13
|
Go to step 9
|
9 |
Check for a loose connection at the yaw rate sensor connector.
Have any problems been found and fixed?
|
-
|
Go to step 13
|
Go to step 10
|
10 |
Replace the yaw rate sensor assembly. See Yaw rate sensorin this section.
Has the renovation been completed?
|
-
|
Go to step 13
|
-
|
11 |
Check the tightness of the connections on the connector of the brake system controller (EBCM).
Have any problems been found and fixed?
|
-
|
Go to step 13
|
Go to step 12
|
12 |
Replace brake controller (EBCM). Cm Brake controllerin this section.
Has the renovation been completed?
|
-
|
Go to step 13
|
-
|
13 |
Is DTC C0292 causing this ignition cycle to fail?
|
-
|
Go to step 2
|
Go to step 14
|
14 |
Use a scan tool to select the DTC display function.
Does the scan tool show any DTC?
|
-
|
Refer to appropriate table for troubleshooting DTCs
|
System OK
|
15 |
Were any deviations found?
|
-
|
Go to step 16
|
Go to step 1
|
16 |
Does the DTC clear?
|
-
|
Go to step 1
|
System OK
|
The steering angle sensor uses a 12V ignition supply in conjunction with the brake controller (EBCM) and a yaw rate sensor. Brake controller (EBCM) applies ground to the low base voltage circuit of the steering angle sensor, which is also used by the yaw rate sensor.
The steering angle sensor provides a serial data output to the brake controller (EBCM), which is the angle of the steering wheel. Brake controller (EBCM) uses this signal to calculate the direction of travel planned by the driver.
This diagnostic works for DTC C0460 - Steering Wheel Position Sensor.
An electrical fault on shared electrical circuits can trigger DTCs on components or sensors that operate on the same faulty circuit. Check the electrical circuit of the relevant sensors or components to locate the fault.
The ignition switch is in the ON position.
If the brake controller (EBCM) detects the following malfunctions of the steering angle sensor:
- internal malfunction of the steering angle sensor,
- steering angle sensor output is out of range or
- steering angle sensor not calibrated.
- Brake controller (EBCM) disables the ABS-TCS/ESP systems for the duration of the ignition cycle.
- In this case, one or more warning indicators may light up:
ABS-TCS warning indicator,
ABS-TCS warning badge,
ESP warning icon,
Brake failure indicator, and/or
Trac-off warning icon.
- The current DTC is moved to the DTC history if during the current brake controller self-test (EBCM) no trouble codes were set.
- Use Tech 2 to clear the DTC.
The following item numbers are step numbers in the diagnostic table:
- Check for the fault that is currently triggering the current DTC.
- Check the common 12V ignition circuit.
- Check the common ground reference circuit.
Step | Operation | Values | Yes | No |
1 |
Has a diagnostic check been run on the system?
|
-
|
Go to step 2
|
Go to item Checking the diagnostic circuitin this section.
|
2 |
Is DTC C0460 causing this ignition cycle to fail?
|
-
|
Go to step 3
|
Skip to More information in this topic
|
3 |
Test the steering angle sensor 12V ignition common circuit for high resistance, open circuit, or short to ground.
Note: The steering angle sensor uses a 12V circuit with the brake controller (EBCM) and a yaw rate sensor. A malfunction in the 12V ignition circuit can set DTCs for components that also operate on that circuit. Have any problems been found and fixed?
|
-
|
Go to step 8
|
Go to step 5
|
4 |
Test the wheel angle sensor common ground circuit for high resistance or an open circuit.
Note: The steering angle sensor shares a reference ground circuit with the yaw rate sensor. A fault in the reference ground circuit can set the Yaw Rate Sensor DTCs. Have any problems been found and fixed?
|
-
|
Go to step 8
|
Go to step 6
|
5 |
Check the tightness of the connections at the steering angle sensor connector.
Have any problems been found and fixed?
|
-
|
Go to step 7
|
Go to step 6
|
6 |
Replace steering angle sensor. See Section 6E, Steering wheel and steering column.
Has the renovation been completed?
|
-
|
Go to step 8
|
-
|
7 |
Is DTC C0460 causing this ignition cycle to fail?
|
-
|
Go to step 2
|
Go to step 9
|
8 |
Use a scan tool to select the DTC display function.
Does the scan tool show any DTC?
|
-
|
Refer to appropriate table for troubleshooting DTCs
|
System OK
|
Internal fault detection occurs within the controller. No external circuits are involved in this process.
This diagnostic procedure resolves the following DTC:
DTC C0550 ECU Performance (ECU)
The microprocessor runs an internal error detection program when a power-on command is received. All that is required is voltage and ground. This program works even when the voltage is out of the allowed operating range.
- The controller detects an internal write error.
- The controller detects an internal checksum error.
If the appropriate hardware is installed, the following actions can occur with the controller:
- The ABS warning lamp lights up.
- The brake warning light comes on.
- The traction control LED goes out (TCS).
- The condition causing the DTC no longer exists.
- Clear DTCs with a scan tool.
- Brake controller (EBCM) automatically clears the DTC history if the current DTC has not been detected in the next 100 cycles.
- This DTC can be stored as a history DTC without affecting the performance of the controller. If the code is only stored as a history DTC, and is not restored as a valid DTC, there is no need to replace the controller.
- If this DTC recovers both as a history and a valid DTC, the controller needs to be replaced.
Step | Operation | Values | Yes | No |
1 |
Have you already performed a Diagnostic System Check on your vehicle?
|
-
|
Go to step 2
|
Go to item Checking the diagnostic circuitin this section.
|
2 |
DTC recovered as current DTC?
|
-
|
Go to step 4
|
-
|
3 |
Replace the controller, setting the fault code as the current code.
Is the replacement completed?
|
-
|
Go to step 4
|
-
|
4 |
Does the DTC clear?
|
-
|
Go to step 2
|
System OK
|
Brake controller (EBCM) recognizes model variants installed internally using vehicle identification information from the body electronics control unit (BCM) via a class 2 serial link. Each time the vehicle is in the RUN state, the body electronics control module transmits this information via a class 2 serial link. Inside the brake controller (EBCM) the vehicle identification number and variant information are compared with the same information stored within the body electronics control unit.
This diagnostic procedure works on the following DTC:
DTC C0551 Variant Configuration Error
- Brake controller (EBCM) detects digits 2 to 9 of the vehicle identification number, not zeros.
- This condition should occur the first time the ignition is turned on.
- Brake controller (EBCM) detects via the body electronics control unit that the options are incorrect, front wheel drive (FWD) or all wheel drive (AWD).
- This condition should occur the first time the ignition is turned on.
If the appropriate hardware is installed, the following actions occur:
- Brake controller (EBCM) disables ABS / traction control (TCS) during the ignition cycle.
- The DTC will be set.
- The ABS indicator lights up
- The traction control indicator lights up.
- The red warning indicator lights up.
- Brake controller (EBCM) recognizes that the information from the body electronics control unit is correct, front-wheel drive (FWD) or all wheel drive (AWD).
- The history DTC will clear after 100 consecutive ignition cycles if the condition for the fault disappears.
- DTC C0551 is set when the brake system controller (EBCM) detects a mismatch between its data and the BCM data by monitoring the BCM message via the class 2 channel.
- If this DTC recovers both as a history and a valid DTC, the controller needs to be replaced.
Step | Operation | Values | Yes | No |
1 |
Have you already performed a Diagnostic System Check on your vehicle?
|
-
|
Go to step 2
|
Go to item Checking the diagnostic circuitin this section.
|
2 |
Are there other DTCs besides DTC C0551?
|
-
|
Go to item Diagnostic trouble codes and their description in this section.
|
Go to step 3
|
3 |
Replace brake controller.
Is the renovation complete?
|
-
|
Go to step 4
|
-
|
4 |
Does the DTC clear?
|
-
|
Go to step 2
|
System OK
|
Brake controller (EBCM) disables the traction control system when other controllers set diagnostic trouble codes for components that interfere with the operation of the traction control system (TCS).
This diagnostic procedure resolves the following DTC:
DTC C0561 System shutdown information stored
This vehicle has DTCs that include DTC symptoms. For more information on DTC symptoms, refer to DTC Symptom Description in Vehicle Diagnostic Trouble Code Information.
- Ignition to the ON position.
- The ignition voltage is greater than 8 volts.
Body electronics control unit (BCM) diagnoses conditions ahead of the traction control engine control unit and sends a serial information message to the brake system controller (EBCM) with an indication of the prohibition of torque reduction. The body electronics control module usually sets a certain DTC, and the brake system controller (EBCM) sets this DTC.
- Brake controller (EBCM) disables traction control until the DTC becomes history.
- The Traction Off indicator lights up.
- Anti-lock braking system (ABS) remains functional.
- The condition for this DTC is no longer present and the DTC is cleared by the scan tool.
- Brake controller (EBCM) automatically clears the archived DTC when the current DTC is not detected for 100 consecutive driving cycles.
This DTC is for information only. To assist mechanics, this DTC indicates that there is nothing wrong with the ABS/TCS system.
Step | Operation | Values | Yes | No |
1 |
Has a diagnostic check been run on the system?
|
-
|
Go to step 2
|
Go to item Checking the diagnostic circuitin this section.
|
Brake controller (EBCM) is the control center for ABS-TCS / ESP systems. The programming and calibration data required by the EBCM to control the operation of the ABS-TCS / ESP systems is stored in the EBCM's ROM. EBCM constantly performs self-tests and localizes errors in ABS-TCS / ESP systems.
This diagnostic works for DTC C0569 - System Configuration Error.
The ignition switch is in the ON position.
If the brake controller configuration (EBCM) does not match the vehicle system configuration.
- Brake controller (EBCM) disables the ABS-TCS/ESP systems for the duration of the ignition cycle.
- In this case, one or more warning indicators may light up:
ABS-TCS warning indicator,
ABS-TCS warning badge,
ESP warning icon,
Brake failure indicator, and/or
Trac-off warning icon.
- The current DTC is moved to the DTC history if during the current brake controller self-test (EBCM) no trouble codes were set.
- Use Tech 2 to clear the DTC.
The following item numbers are step numbers in the diagnostic table:
- Incorrect vehicle system configuration may cause this DTC to occur.
Step | Operation | Values | Yes | No |
1 |
Has a diagnostic check been run on the system?
|
-
|
Go to step 2
|
Go to item Checking the diagnostic circuitin this section.
|
2 |
DTC recovered as current DTC?
|
-
|
Go to step 3
|
Go to step 4
|
3 |
Have any problems been found and fixed?
|
-
|
Go to step 5
|
Go to step 4
|
4 |
Replace EBCM.
Has the renovation been completed?
|
-
|
Go to step 5
|
-
|
5 |
Is DTC C0569 causing this ignition cycle to fail?
|
-
|
Go to step 2
|
Go to step 6
|
6 |
Use a scan tool to select the DTC display function.
Does the scan tool show any DTC?
|
-
|
Refer to the corresponding table for troubleshooting instructions for DTCs.
|
System OK
|
Brake controller (EBCM) monitors the voltage level while the system is running. Low voltage interferes with the correct operation of the system.
This diagnostic procedure works on the following DTC:
DTC C0899 Device Voltage Low
- Vehicle speed over 8 km/h (5 mph).
- The system relay has been commanded to turn on.
- During initialization or when the system is idle, the system voltage is less than 10.8 volts.
- The system voltage is less than 9.0 volts during system operation.
If the appropriate hardware is installed, the following actions occur:
- Brake controller (EBCM) disables the ABS system for the duration of the ignition cycle.
- The ABS indicator lights up.
- The traction control indicator lights up.
- DTC C0899 is stored.
- The condition for this DTC is no longer present and the DTC is cleared by the scan tool.
- Brake controller (EBCM) automatically clears the DTC history if the current DTC has not been detected in the next 100 cycles.
- Check charging system.
- Possible causes for this DTC to set are:
- The battery is not sufficiently charged or discharged.
- Poor contact with battery terminal.
- Excessive current draw on a factory or replacement battery.
- Poor battery case or chassis contact "weight".
- Poor contact with the brake system controller (EBCM).
- Bad contact of the brake system controller (EBCM) with mass.
- Charging system malfunction (generator).
- Carefully inspect the wires and connectors. If a careful and complete inspection of the wires and connectors is not performed, this may entail the replacement of parts, and the malfunction will remain unrepaired.
Step | Operation | Values | Yes | No |
1 |
Is the diagnostic circuit test completed?
|
-
|
Go to step 3
|
Go to step 2
|
2 |
Perform a diagnostic circuit test.
Is there any fault found?
|
-
|
Go to step 3
|
System OK
|
3 |
Is the voltage within the required range?
|
9.4...17 V
|
Go to step 4
|
Go to step 5
|
4 |
Replace EBCM.
Check the diagnostic circuit again. Is there any fault found?
|
-
|
Go to step 1
|
System OK
|
5 |
Check the voltage between the positive and negative terminals of the battery.
Is the voltage within the required range?
|
9.4...17 V
|
Go to step 7
|
Go to step 6
|
6 |
Replace battery
|
-
|
Go to step 1
|
-
|
7 |
Check the resistance between track 22 of the brake controller connector (EBCM) and the positive terminal of the battery.
Is the resistance within the required range?
|
less than 1 ohm
|
Go to step 9
|
Go to step 8
|
8 |
|
-
|
-
|
-
|
9 |
Check resistance between terminals 16 and G104.
Is the resistance within the required range?
|
less than 1 ohm
|
Go to step 11
|
Go to step 10
|
10 |
Repair or replace the brake controller connector (EBCM) or G104.
|
-
|
Go to step 1
|
-
|
11 |
Is it in the required range?
|
less than 17 V
|
Go to step 1
|
Go to step 12
|
12 |
Repair or replace generator as needed.
|
-
|
Go to step 1
|
-
|
Brake controller (EBCM) monitors the voltage level while the system is running. If the voltage level is too high, it may cause damage to the system. When the brake controller (EBCM) detects a high voltage condition, it deactivates the system relay which removes battery voltage from the solenoid valves and the pump motor.
This diagnostic procedure resolves the following DTC:
DTC C0900 Device Voltage High
Vehicle speed over 8 km/h (5 mph).
System voltage exceeds 17 volts in 0.72 seconds.
If the appropriate hardware is installed, the following actions occur:
- Brake controller (EBCM) disables the ABS system for the duration of the ignition cycle.
- The ABS indicator lights up.
- The traction control and active control indicators light up.
- The solenoid valve relay opens, removing power from the solenoid valves and the pump motor.
- DTC C0900 is stored in memory.
- The condition for this DTC is no longer present and the DTC is cleared by the scan tool.
- Brake controller (EBCM) automatically clears the DTC history if the current DTC has not been detected in the next 100 cycles.
A possible cause for this DTC is overcharging.
Step | Operation | Values | Yes | No |
1 |
Is the diagnostic circuit test completed?
|
-
|
Go to step 3
|
Go to step 2
|
2 |
Perform a diagnostic circuit test.
Is there any fault found?
|
-
|
Go to step 3
|
System OK
|
3 |
Is the voltage within the required range?
|
9.4...17 V
|
Go to step 4
|
Go to step 5
|
4 |
Replace EBCM.
Check the diagnostic circuit again. Is there any fault found?
|
-
|
Go to step 1
|
System OK
|
5 |
Check the voltage between the positive and negative terminals of the battery.
Is the voltage within the required range?
|
9.4...17 V
|
Go to step 7
|
Go to step 6
|
6 |
Replace battery
|
-
|
Go to step 1
|
-
|
7 |
Check the resistance between track 22 of the brake controller connector (EBCM) and the positive terminal of the battery.
Is the resistance within the required range?
|
less than 1 ohm
|
Go to step 9
|
Go to step 8
|
8 |
|
-
|
-
|
-
|
9 |
Check resistance between terminals 16 and G104.
Is the resistance within the required range?
|
less than 1 ohm
|
Go to step 11
|
Go to step 10
|
10 |
Repair or replace the brake controller connector (EBCM) or G104.
|
-
|
Go to step 1
|
-
|
11 |
Is it in the required range?
|
less than 17 V
|
Go to step 1
|
Go to step 12
|
12 |
Repair or replace generator as needed.
|
-
|
Go to step 1
|
-
|
Units connected to high speed GMLAN serial data circuits monitor serial communications during normal vehicle operation. Between the blocks there is an exchange of information about the work and the exchange of commands. The blocks contain information about what messages need to be exchanged over serial data chains for each virtual network. Messages are monitored and some regular messages are used by the receiving unit as indicators of the readiness of the transmitting units.
This diagnostic procedure supports the following DTCs:
- DTC U0102 Lost Communication with RDM (Rear drive unit)
- DTC U2105 Lost Communication With ECM
- DTC U2106 Lost Communication With TCM
- DTC U2107 Lost Communication With Body Electronics Control Module (BCM)
- DTC U2139 Lost Communication with Gateway
- DTC U2142 Sensor Group Communication Lost
- DTC U2143 Steering Angle Sensor Lost Communication
- The voltage supplied to the units is within the normal operating voltage range.
- The power supply mode of the car determines the need for a serial communication session.
A monitored regular message was not received, including a signal about the readiness of the transmitting unit.
The block uses the default value for the missing parameter.
- The current DTC is cleared when the fault disappears.
- A history DTC is cleared when the block ignition cycle counter reaches the reset threshold, assuming there is no malfunction.
- The setting of this DTC may be due to a loose connection on the idle unit.
- The setting of this DTC may be due to improper power supply to the module.
Step | Operation | Values | Yes | No |
1 |
Has a diagnostic check been run on the circuit?
|
-
|
Go to step 2
|
Go to item Checking the diagnostic circuitin this section.
|
2 |
Important: Use the list of diagnostic trouble codes in the diagnostic trouble code descriptors to locate the module that is not responding. Test the following circuits in the unresponsive module for an open circuit or short to ground:
Was the fault condition found and corrected?
|
-
|
Go to step 7
|
Go to step 3
|
3 |
Was the fault condition found and corrected?
|
-
|
Go to step 7
|
Go to step 4
|
4 |
Test the non-responding unit's high speed GMLAN serial data circuits for an open.
Was the fault condition found and corrected?
|
-
|
Go to step 7
|
Go to step 5
|
5 |
Check the wiring harness connectors of the non-responding unit for loose connections and tension on the contacts in the following circuits:
Was the fault condition found and corrected?
|
-
|
Go to step 7
|
Go to step 6
|
6 |
Replace the unit that is not responding.
Is the replacement completed?
|
-
|
Go to step 7
|
-
|
7 |
A scan tool must be used to clear DTCs.
Is the scan tool still displaying other current DTCs?
|
-
|
Skip to Diagnostic Circuit Verification in this section.
|
-
|
Units connected to the GMLAN serial data circuits monitor serial communications during normal vehicle operation. Between the blocks there is an exchange of information about the work and the exchange of commands. Body electronics control unit (BCM) maintains the operation of the transmit unit error counter (TEC) and receiving block error counter (REC). The counters are incremented as errors are found and decremented when messages without errors are received.
This diagnostic procedure resolves the following DTC:
- DTC U1500 Communication Malfunction on CAN Bus 2 (group of sensors) (Bus disabled)
- DTC U2100 CAN Bus Communication Malfunction (Bus disabled)
- The voltage supplied to the unit is within the normal operating voltage range.
- The power supply mode of the car determines the need for a serial communication session.
The block detects a number of invalid messages transmitted over the GMLAN serial data circuit. The engine will not start while a general fault condition exists on the GMLAN serial data circuits with the engine off. The following conditions can result in the complete loss of all high-speed GMLAN communications:
- Short circuit between GMLAN high speed circuit (+) and high speed GMLAN circuit (-)
- Any high speed GMLAN serial data circuit is shorted to ground or voltage
- Internal unit failure that causes a short to voltage or ground on high speed GMLAN circuits
- An open in any GMLAN high speed serial data circuit
- This block stops the transmission of all messages.
- For all parameters received over the high speed GMLAN serial data circuits, the block applies default values.
- The block inhibits the setting of all other high speed GMLAN DTCs.
- The current DTC is cleared when the fault disappears.
- A history DTC is cleared when the block ignition cycle counter reaches the reset threshold, assuming there is no malfunction.
The BCM can set this DTC as the current DTC because it is a gateway between the class 2 serial data circuits and the high speed GMLAN circuits and the BCM diagnostics are performed on a class 2 network.
The high speed GMLAN serial data bus uses two 120 ohm terminating resistors in parallel with the high speed GMLAN circuits (+) And (-). One of the resistors is connected to the BCM and the other to the ECM. When testing for a short circuit between high-speed GMLAN circuits (+) And (-) a resistance of 60 ohms is normal. If there is an open on the high speed GMLAN serial data bus, when checking the resistance between the high speed GMLAN circuits (+) And (-) resistance will be about 120 ohms.
Step | Operation | Values | Yes | No |
1 |
Has a diagnostic check been run on the circuit?
|
-
|
Go to step 2
|
Go to item Checking the diagnostic circuitin this section.
|
2 |
Is DTC U2100 or U1500 recorded as current codes?
|
-
|
Go to step 4
|
Go to step 3
|
3 |
Important: When checking for a short to voltage, turn the ignition switch to the on position (ON), but do not start the engine. Use the MIN/MAX function of the digital multimeter to detect intermittent conditions. Check high speed GMLAN serial data circuits for:
Was the fault condition found and corrected?
|
-
|
Go to step 15
|
Go to step 6
|
4 |
Is DTC U2100 still showing as current?
|
-
|
Go to step 5
|
Go to step 9
|
5 |
Is DTC U2100 still showing as current?
|
-
|
Go to step 7
|
Go to step 6
|
6 |
Check the high speed GMLAN serial data circuits between the last two disconnected units for:
Was the fault condition found and corrected?
|
-
|
Go to step 12
|
Go to step 9
|
7 |
Is the BCM the last unit connected to the high speed GMLAN circuits?
|
-
|
Go to step 8
|
Go to step 5
|
8 |
Was the fault condition found and corrected?
|
-
|
Go to step 12
|
Go to step 10
|
9 |
Test each high speed GMLAN serial data circuit between the last disconnected unit and the unit closest to the DLC connector for an open circuit.
Was the fault condition found and corrected?
|
-
|
Go to step 12
|
Go to step 10
|
10 |
Check the high-speed GMLAN serial data connections of the suspect unit for continuity.
Was the fault condition found and corrected?
|
-
|
Go to step 12
|
Go to step 11
|
11 |
Replace the suspect block.
Is the replacement completed?
|
-
|
Go to step 12
|
-
|
12 |
Are there fault codes that begin with "U" and are they recorded in their current state?
|
-
|
Go to Diagnostic Trouble Codes in this section.
|
Go to step 13
|
13 |
Are there fault codes that do not start with "U"?
|
-
|
Go to Diagnostic Trouble Codes in this section. Step 12
|
Go to step 14
|
14 |
Have all trouble codes been diagnosed?
|
-
|
Go to step 15
|
Go to step 12
|
15 |
A scan tool must be used to clear DTCs.
Action completed?
|
-
|
System OK
|
-
|