Symptoms of Engine Control Failures (Chevrolet Captiva 1)

Important Preliminary Checks

Before using this section, you must perform the "Diagnostic System Check" described in this section and verify that all of the following conditions are met:

The ECM and Malfunction Indicator Lamp are functioning properly.
There are no diagnostic trouble codes (DTCs) stored in memory.
Scan tool data is within normal operating range.
Check the customer's complaints and correctly identify the symptoms of the malfunction. Check everything that is indicated in relation to this symptom of the malfunction.
The procedures provided for some signs require a thorough visual/physical inspection. This step is extremely important and can allow the fault to be corrected without further inspection, saving time.
Check that the following optional equipment, not installed at the factory, is installed correctly:

Lighting fixtures
Cell phone
Remote engine start system
Security alarm not installed by the manufacturer

Visual and physical inspection

Check the following:

Make sure the controller ground connections are clean, tight, and properly positioned.
Check the vacuum hoses for integrity, absence of knots and secure connection.
Check the wiring:
Correctness of connections.
Compressions
Incisions

The table below provides groups of possible causes for each symptom. The order in which you perform these procedures does not matter. If the scan tool readings do not indicate a problem, proceed in a logical order, starting with the easiest tests or most likely causes.

Checking customer complaints

Select the table for the appropriate symptom. Perform the tests specified for the present symptom from the following symptom tables:

Intermittent faults
Difficult start
Pops/shots in the silencer
Lack of power and throttle response, soft pedal effect
Detonation / combustion noise
Delays, failures, jerks
Engine misfires; Delays, failures
High fuel consumption
Rough, erratic or improper idling or stalling
Excessive exhaust smoke

Intermittent faults

Inspections	Operation, action
Definition: There is currently no fault present, but it is contained in the DTC history. Definition: OR Definition: There is a customer complaint, but the fault cannot be reproduced at this time unless it is related to a diagnostic trouble code.
Preliminary	See the "Important Preliminary Checks" section in "Signs of malfunction. Engine controls." To determine the cause using the diagnostic trouble code table, the malfunction must be present at the moment. If the malfunction is intermittent, then using the diagnostic trouble code table may lead to the replacement of serviceable units.
Visual / physical	This step can be important to identify the problem without extensive testing. Perform a thorough visual and physical inspection of the following components. Wiring harnesses for damage and cuts Incorrectly placed harnesses located too close to devices handling high voltages or currents, such as the following: Electric motors Generators Vacuum hoses: Correct placement Correctness of connections Cracks in hoses or connections Kinks and knots The ground connections on the controller and body are clean and tight. Battery connections are clean and tight The charging system is in good working order.
Checking the harness/connector	Many intermittent opens or shorts in circuits come and go due to movement of harnesses and connectors caused by vibration, engine torque, shock, uneven road surfaces, etc. Check for this type of fault by performing the following procedure: Move the appropriate connectors and wiring while monitoring the relevant data on the scan tool. Wiggle the appropriate connectors and wiring while simultaneously sending commands from the scanning device to the component being tested to turn it on and off. Monitor the operation of the components. With the engine running, move the corresponding connectors and wiring while simultaneously observing the engine operation. If movement of a harness or connector affects the data displayed on the display, the operation of components and systems, or the engine, inspect the harnesses and connectors and make any necessary repairs.
Electrical connections and wiring	Most intermittent faults are caused by poor electrical connections, poor mechanical contact between connector pins, or wiring errors. Carefully inspect suspect circuits for the following faults: Incorrect connection of connector halves, incomplete insertion of contacts into the connector, or bent contacts. Check for deformation or damage to the terminals. Unreliable mechanical connection of the connector contacts. Bad connections of contacts and wires, including contacts crimped through insulation. Requires removal of terminal from connector body. Corrosion or moisture penetration. Moisture can penetrate wiring that has punctures or damaged insulation. The conductor can corrode under the insulation and be barely noticeable from the outside. Swollen or stiff sections of wire in suspect circuits. Wires with breaks located under the insulation. Harnesses that have punctured, cut or frayed insulation. Prevent electrical wiring from coming into contact with hot components of the exhaust system.
Power supply and ground connections of the controller	Faulty power supply or ground connections can cause a variety of faulty symptoms. All power circuits to the controller must be checked. On many vehicles, power is supplied to the controller through several circuits. Check the controller connector connections, fuses, and all intermediate connections between the power source and the controller or component. A test light or digital voltmeter can be used to determine if voltage is present, but cannot be used to check the current-carrying capacity of the circuits. Check if the circuit has sufficient current-carrying capacity to operate the component. Check all controller and system ground circuits. The controller may have multiple ground circuits. Other system components may have separate ground connections that may also need to be checked. Ground connections must be clean and securely tightened at the connection point. Check connections at the component and terminal blocks, where applicable. Check that the circuit has sufficient current-carrying capacity to operate the component.
Temperature sensitivity	Some intermittent faults may only occur if the component is cold or if it is hot. The source of heat affecting the circuit may be the motor, a poor connection in the circuit, or a high electrical load. Customer interviews may help determine if the fault is temperature related. Where appropriate, Failure Status Records/Logs or Snapshot Mode data may be useful for this type of intermittent fault. If the intermittent fault is related to heat exposure, then analyze the data for a relationship with the following: High ambient temperatures Heat coming from under the hood/from the engine A circuit that generates heat due to a poor connection or high electrical load Exceeding normal load (towing, etc.) If the intermittent fault is related to cold, then analyze the data for a connection with the following: Low ambient temperatures At very low temperatures, ice may form on connections or components. Check for moisture penetration. The malfunction occurs only during cold start. The malfunction disappears after the engine warms up.
Electromagnetic interference and electromagnetic noise	Some electrical components and circuits are sensitive to electromagnetic interference or other types of electrical noise. Check the following: Incorrectly placed harnesses, located too close to devices that operate with high voltages or currents, such as electric motors, generators, etc. These components can be a source of electrical noise that affects the circuit and interferes with its normal operation. Electromagnetic interference in electrical systems caused by faulty relays, solenoid valves or switches controlled by controllers. They can cause sudden voltage spikes. The problem usually occurs when the faulty component is operating. Improper installation of non-factory, after-sales, or additional auxiliary equipment, such as lighting devices, radio receiving and transmitting devices, amplifiers, electric motors, remote-controlled starters, security alarm systems, cell phones, etc. Check the diode in the air conditioner compressor clutch and other diodes for an open circuit. Some relays may have a limiting diode or resistor.
Incorrect programming of the controller	Reprogramming the controller is only permissible in certain cases: A new controller has been installed. A new version of software/calibration files has been released for the vehicle. Important: DO NOT reprogram the controller using OLD software/calibration files that are already in the controller. This troubleshooting method is not effective for all types of driveability issues. Ensure that the controller contains the required software/calibration. If incorrect software is found, reprogram the controller with the latest software/calibration.
Reproducing the conditions of the fault occurrence	If the previous tests were unsuccessful, attempt to reproduce and/or record the conditions under which the DTC set. The Freeze Frame/Failure Records data contains, if applicable, the conditions under which the DTC set. View and record status record/fault log information. Using a scan tool, clear all DTCs. Turn the key to the OFF position and wait 15 seconds Reproduce the same conditions as those found in the vehicle Freeze Frame/Failure Records. The conditions for setting the DTC must also be met. Refer to the "Conditions for Setting the DTC" section of the corresponding diagnostic trouble code description. Monitor the DTC status for the malfunction in question. Once the conditions required for the DTC have been met long enough for the DTC to set, the scan tool will display "Ran". The scan tool will also indicate whether the diagnostic for that DTC has passed or failed. The second possible method is to drive the car with a digital multimeter connected to the suspect circuit. Deviations from the normal readings of the multimeter when a fault occurs can help determine its cause.
Operation of the scanning device in the "snapshot" mode	The scan tool can be switched to the "snapshot" mode of parameters received via the serial data channel. In the "snapshot" mode, current data is recorded over a specified period of time. The recorded data can be viewed and analyzed. In addition, the scan tool can plot graphs for individual parameters or for a group for comparison purposes. The "snapshot" mode can be turned on manually, at the moment a malfunction is detected, or selected in advance to be turned on at the moment a diagnostic trouble code is set. An abnormal value in the recorded data may help identify a system or component that should be checked. For more information on the Snapshot mode, refer to the scan tool instruction manual.

Difficult start

Inspections	Operation, action
Definition: The engine cranks normally, but the engine fails to start for a long time. The engine eventually starts, or may start but immediately stall.
Preliminary inspection	Go to item Signs of malfunction. Engine controls. Make sure the driver performs the start correctly.
Checking the sensor	Check the engine coolant temperature (ECT) sensor. Use a scan tool to compare the coolant temperature to the ambient temperature when the engine is cold. If the coolant temperature is 5 degrees higher or lower than the ambient temperature when the engine is cold, check the ECT sensor circuit or the sensor itself for high electrical resistance. Turn the ignition on with the engine off. Using a scan tool, determine the actual fuel rail pressure. The actual fuel rail pressure (FRP) sensor signal voltage should be approximately 0.5 V. If not, check for high resistance in the sensor circuit or the sensor itself. Check the correct installation and serviceability of the connection at the camshaft position sensor (CMP) and the crankshaft position sensor (CKP).
Checking the fuel system	Check the fuel pressure regulator circuits for intermittent shorts to ground. Check the fuel supply to the fuel injection pump. Check if the fuel filter is clogged. Check for air in the fuel system. Check for external fuel leaks. Check the oil level, which should not be too high. Check the fuel pressure, which should not be too low. Check the serviceability of the fuel tank cap ventilation valve.
Checking the electrical system	Check the crankshaft speed when starting the engine.
Checking the air intake system	Check the air filter and air intake ducts for any obstructions or leaks. Check the turbocharger intake duct to ensure there are no obstructions to the air flow. Check the intake manifolds for any obstructions or leaks.
Checking the exhaust system	Check the exhaust system to ensure that there are no obstructions to the flow of gases.
Checking the mechanical part of the engine	Inspect the engine for the following faults: Incorrect valve timing adjustment Bent tappets Wear of rocker arms Low engine compression Broken or weakened valve springs Worn camshaft lobes
Additional checks	Check the crankshaft angle sensor for an intermittent fault using its signal. See "Intermittent faults." Check the Operation and Service Bulletins to see if there is information about a new version of the controller software.

Pops/shots in the silencer

Inspections	Operation, action
Definition: Engine power changes with a constant throttle position or constant speed. The vehicle speeds up and down without changing the position of the gas pedal.
Preliminary inspection	Go to item Signs of malfunction. Engine controls. Ensure the driver understands how the torque converter clutch (TCC) operates. Make sure the driver understands how the air conditioning compressor works. Using a scan tool, verify that the vehicle speed sensor (VSS) reading matches the speedometer reading. This does not apply to vehicles with "electronic" transmissions, where some difference between the VSS and speedometer readings is not abnormal.
Checking the sensor	Turn the ignition on with the engine off. Using a scan tool, determine the actual fuel rail pressure. The actual fuel rail pressure (FRP) sensor signal voltage should be approximately 0.5 V. If not, check for high resistance in the FRP sensor circuit or the FRP sensor itself. Check the FRP sensor for an intermittent fault using its signal by moving the harness between the sensor and the ECM with the ignition on and the engine off, while simultaneously monitoring the parameter status using a scan tool. Check the correct installation and/or serviceability of the connection at the camshaft position sensor (CMP) and the crankshaft position sensor (CKP).
Checking the fuel system	Check the vacuum in the fuel system if there is a malfunction. Check for a stuck fuel pressure regulator. A symptom of this malfunction is a sudden change in idle speed of at least 100 rpm. This change can occur in the range from 50 rpm higher than the required idle speed to 50 rpm lower than the specified speed.
Additional checks	Make sure the controller ground connections are clean, tight, and properly positioned. Check the generator output voltage. Fix the problem if the voltage is less than 9 V or more than 16 V. Check the operation of the torque converter clutch.

Lack of power and throttle response, soft pedal effect

Inspections	Operation, action
Definition: The engine produces less power than expected. The vehicle accelerates little or not at all when the accelerator pedal is not fully depressed.
Preliminary inspection	Go to item Signs of malfunction. Engine controls. Check fuel filters. Aftermarket fuel filters can restrict fuel flow. Compare with a car with the same device. Make sure that the car really has a malfunction. Remove the air filter and check it for dirt and check the air ducts for blockages or leaks. Repair or replace if necessary. Check the proper operation of the gearbox. Check the level and quality of engine oil.
Checking the sensor	Check the correct installation and serviceability of the connection at the camshaft position sensor (CMP) and the crankshaft position sensor (CKP).
Checking the fuel system	Check the fuel supply to the fuel injection pump Using a scan tool, compare the actual and required fuel pressure in the fuel rail with the engine idling. Check the engine speed signal circuit for high resistance. Check the fuel injectors for any obstructions or blockages.
Exhaust system checks	Check the exhaust system to ensure that there are no obstructions to the flow of gases.
Air Intake System Checks	Check the intake air ducts and intake manifold for any obstructions or leaks. Check the charge air cooler for leaks or obstructions to air flow. Check the turbocharger turbine wheel and shaft, as well as the turbocharger impeller, which must not be worn or damaged. Check the mass air flow (MAF) sensor for a systematic error.
Checking the mechanical part of the engine	Check the engine for the following faults: Low compression ratio Incorrect valve timing adjustment An error was made when selecting the camshaft or the shaft is worn out
Additional checks	Make sure the controller ground connections are clean, tight, and properly positioned. Check the operation of the torque converter clutch (TCC). Check the operation of the air conditioning system. Check the generator output voltage.

Detonation / combustion noise

Inspections	Operation, action
Definition: A light or loud knocking noise that usually gets worse with acceleration. The engine produces sharp metallic knocking sounds that change as the accelerator pedal is pressed.
Preliminary checks	Go to item Signs of malfunction. Engine controls. Make sure that the car actually has a fault Find out what kind of exhaust smoke accompanies the detonation. Refer to the section "Fuel system checks" below.
Cooling system checks	Check for obvious signs of overheating. Check the engine coolant level, which should not be low. Check if air movement through the radiator is obstructed. Check whether the thermostat is working properly and whether there was a mistake made when selecting it. Check if there was an error in choosing the composition of the coolant. The composition should be a mixture of antifreeze and water in a 50/50 ratio.
Checking the sensor	Using a scan tool, check the coolant temperature (ECT) sensor to compare the ECT to the ambient temperature when the engine is cold. If the coolant temperature is 5 degrees higher or lower than the ambient temperature when the engine is cold, check the coolant temperature sensor circuit or the sensor itself for high resistance. Turn ignition on with engine off. Using a scan tool, determine actual fuel rail pressure (FRP). FRP sensor signal voltage should be approximately 0.5 V. If not, check for high resistance in FRP sensor circuit or FRP sensor itself. Check the crankshaft position (CKP) sensor for an intermittent fault based on its signal. See "Intermittent faults." Check the correct installation and serviceability of the connection at the camshaft position sensor (CMP) and the crankshaft position sensor (CKP).
Fuel system checks	If there is excessive exhaust smoke, check to see if the fuel injector is stuck open. Check the fuel injectors, which should not be clogged.
Checking the mechanical part of the engine	Check if there is an error in the selection of the main engine parts, such as the camshaft, heads, pistons, etc. Check to see if too much oil is entering the combustion chamber.
Additional checks	Check the Operation and Service Bulletins to see if there is information about a new version of the controller software.

Delays, failures, jerks

Inspections	Operation, action
Definition: After pressing the accelerator pedal, there is no engine response for a short time. This malfunction can occur at any vehicle speed. Usually, the malfunction is especially noticeable when the vehicle starts moving. If the malfunction is noticeable enough, the engine may stall.
Preliminary inspection	Go to item Signs of malfunction. Engine controls.
Checking the fuel system	Check the vacuum in the fuel system. Check for water in the fuel. Check the balance of the injectors. Check the vacuum in the high pressure fuel system after a cold start or during moderate to full throttle opening during acceleration.
Checking the sensor	Turn ignition on with engine off. Using a scan tool, determine actual fuel rail pressure (FRP). FRP sensor signal voltage should be approximately 0.5 V. If not, check for high resistance in FRP sensor circuit or FRP sensor itself. Check the FRP sensor for an intermittent fault using its signal by moving the harness between the sensor and the ECM with the ignition on and the engine off, while simultaneously monitoring the parameter status using a scan tool. Check the crankshaft position (CKP) sensor for an intermittent fault based on its signal. See "Intermittent faults." Check the correct installation and serviceability of the connection at the camshaft position sensor (CMP) and the crankshaft position sensor (CKP).
Additional checks	Check the Operation and Service Bulletins to see if there is information about a new version of the controller software. Check the generator output voltage.

Engine misfires; Delays, failures

Inspections	Operation, action
Definition: A constant jerking noise that accompanies engine operation, usually more noticeable as engine load increases, usually not noticeable above 1500 rpm or 48 km/h (30 miles/hour). Exhaust gases make a constant hissing sound at idle, low revs or heavy acceleration due to insufficient fuel supply, which can lead to engine stalling.
Preliminary inspection	Go to item Signs of malfunction. Engine controls. Compare the scan tool idle data with the scan tool data list.
Checking the sensor	Check the crankshaft position sensor (CKP) for an intermittent fault based on its signal. Check the correct installation and serviceability of the connection at the camshaft position sensor (CMP) and the crankshaft position sensor (CKP).
Checking the mechanical part of the engine	Perform an engine compression test Inspect the engine for the following faults: Incorrect valve timing adjustment Bent tappets Wear of rocker arms Worn camshaft lobes Broken or weakened valve springs Check the intake and exhaust manifold channels for burrs.
Checking the fuel system	Check the fuel system, in which the fuel filter should not be clogged, there should not be a strong vacuum, air, etc. Check for water in the fuel. Check the proper operation of the fuel injectors.

High fuel consumption

Inspections	Operation, action
Definition: Fuel consumption measured in real road tests and over several tank fills is significantly higher than expected. Also, fuel consumption is significantly higher than measured in previous road tests of this vehicle.
Preliminary inspection	Go to item Signs of malfunction. Engine controls. Check the air filter for dirt or blockage. Check for air leaks in the charge air cooler. Check the operation of the air conditioning system. Check the air pressure in the tires. Check the owner's driving style. Are heavy loads transported? Recommend the owner to fill the fuel tank and determine the fuel consumption.
Checking the sensor	Check the crankshaft position sensor (CKP) for an intermittent fault based on its signal. Check the correct installation and serviceability of the connection at the camshaft position sensor (CMP) and the crankshaft position sensor (CKP).
Checking the fuel system	Check the type and quality of fuel. Check the vacuum in the fuel system.
Checking the cooling system	Check the coolant level. Check that the engine thermostat does not remain permanently open and that the correct heat range is selected.
Additional checks	Check the proper operation of the gearbox. Check the operation of the torque converter clutch (TCC). When the TCC is commanded ON, the scan tool should show a drop in RPM. Check the Operation and Service Bulletins to see if there is information about a new version of the controller software. Check the brakes for proper operation.

Uneven, unstable idling or incorrect idling speed and engine stop

Inspections	Operation, action
Definition: The engine idles unevenly. If a noticeable malfunction occurs, the engine or car may shake. The idle speed may vary. Any of these malfunctions, if noticeable, can be enough to stop the engine.
Preliminary inspection	See the "Important Preliminary Checks" section in "Signs of malfunction. Engine controls." Look for recommendations in the newsletters. Check if the vehicle has any additional equipment installed at the factory or after sales, which may come into contact with the body or chassis. Failure to connect to the "mass" can manifest itself as a missing ignition or uneven operation. Ensure that the ECM ground connections are clean, tight, and properly located. Remove and check the air filter element, it should not be dirty or clogged. Replace if necessary.
Checking the sensor	Turn ignition on with engine off. Using a scan tool, determine actual fuel rail pressure (FRP). FRP sensor signal voltage should be approximately 0.5 V. If not, check for high resistance in FRP sensor circuit or FRP sensor itself. Check the FRP sensor for an intermittent fault using its signal by moving the harness between the sensor and the ECM with the ignition on and the engine off, while simultaneously monitoring the parameter status using a scan tool. Check the crankshaft position sensor (CKP) for an intermittent fault based on its signal. Check the correct installation and serviceability of the connection at the camshaft position sensor (CMP) and the crankshaft position sensor (CKP). Check crankcase ventilation.
Checking the fuel system	Check the balance of the injectors. Check if the fuel filter is clogged. Check if the fuel is contaminated. Check for a stuck fuel pressure regulator. A symptom of this malfunction is a sudden change in idle speed of at least 100 rpm. This change can occur in the range from 50 rpm higher than the required idle speed to 50 rpm lower than the specified speed.
Checking the mechanical part of the engine	Check the mechanical part of the engine: Check cylinder compression Sticking or leaking valves Worn camshaft lobes Adjusting the valve timing Bent tappets Wear of rocker arms Broken valve springs Excessive amount of oil in the combustion chamber Check if there is a mistake in selecting the following main engine parts: Camshaft Cylinder heads Pistons, connecting rods or bearings
Additional checks	Check for obstructions to gas flow in the following components of the exhaust system: Damaged or crushed exhaust pipes Crumpled inner wall of the exhaust manifold Temperature deformation or possible internal failure of the mufflers Electromagnetic interference in the reference circuit can cause ignition interruptions. Typically, a scanning device can detect electromagnetic interference by monitoring the engine speed. A sudden increase in the measured speed with a slight change in the actual speed indicates the effect of electromagnetic interference. If there is such a fault, check the placement of high-voltage components, such as fuel injector wiring, near the sensor circuits. Check the park/neutral position (PNP) switch circuit. Check the serviceability of the engine mounts. Check the intake manifold and exhaust manifold passages for burrs.

Excessive exhaust smoke (gray or blue)

Inspections	Operation, action
Definition: Gray or blue exhaust smoke under load, at idle, or when starting a hot or cold engine.
Preliminary inspection	Go to item Signs of malfunction. Engine controls. Make sure that the car actually has a fault. Check the coolant level in the tank. White smoke produced by the coolant may be mistaken for blue or gray smoke. If the coolant level is low, then contact the following service provider: Part 1D. "Engine Cooling".
Checking the fuel system	Using a scan tool, compare the actual and required fuel pressure in the fuel rail while the engine is running. Check the fuel injectors.
Checking the sensor	Check the engine coolant temperature (ECT) sensor. Use a scan tool to compare the coolant temperature to the ambient temperature when the engine is cold. If the coolant temperature is 5 degrees higher or lower than the ambient temperature when the engine is cold, check the coolant circuit or the sensor itself for high electrical resistance. Turn ignition on with engine off. Using a scan tool, determine actual fuel rail pressure (FRP). FRP sensor signal voltage should be approximately 0.5 V. If not, check for high resistance in FRP sensor circuit or FRP sensor itself.
Checking the air intake system	Check for obstructions in the air filter and air intake ducts. Check if the mass air flow (MAF) sensor is dirty. Check for obstructions to the air flow in the turbocharger charge air cooler. Check if there are any obstructions to the air flow in the intake manifold.
Checking the mechanical part of the engine	Check for leaks from the cylinders. Perform an engine compression test. Check if there is an error in the selection of key engine parts such as the camshaft, heads, pistons, piston rings and valves. Check to see if too much oil is entering the combustion chamber.
Checking the turbocharger	Check for leaks at turbocharger seals.

Excessive exhaust smoke (white)

Inspections	Operation, action
Definition: White exhaust smoke under load, at idle, or when starting a hot or cold engine.
Preliminary inspection	Go to item Signs of malfunction. Engine controls. Make sure that the car actually has a fault. Check the coolant level in the tank. White smoke produced by the coolant may be mistaken for blue or gray smoke. If the coolant level is low, then contact the following service provider: Part 1D. "Engine Cooling".
Checking the fuel system	If there is excessive exhaust smoke, check to see if the fuel injector is stuck open. Check the fuel injectors, which should not be clogged.
Checking the sensor	Check the engine coolant temperature (ECT) sensor. Use a scan tool to compare the coolant temperature to the ambient temperature when the engine is cold. If the coolant temperature is 5 degrees higher or lower than the ambient temperature when the engine is cold, check the coolant circuit or the sensor itself for high electrical resistance. Turn ignition on with engine off. Using a scan tool, determine actual fuel rail pressure (FRP). FRP sensor signal voltage should be approximately 0.5 V. If not, check for high resistance in FRP sensor circuit or FRP sensor itself.
Checking the air intake system	Check for obstructions in the air filter and air intake ducts. Check for obstructions to the air flow in the turbocharger charge air cooler. Check if there are any obstructions to the air flow in the intake manifold.
Checking the mechanical part of the engine	Check if there is an error in the selection of the main engine parts, such as the camshaft, heads, pistons, etc. Check that no coolant is entering the combustion chamber.

Excessive exhaust smoke (black)

Inspections	Operation, action
Definition: Black exhaust smoke under load, at idle, or when starting a hot or cold engine.
Preliminary inspection	Go to item Signs of malfunction. Engine controls. Make sure that the car actually has a fault.
Checking the fuel system	Using a scan tool, compare the actual and required fuel pressure in the fuel rail while the engine is running. Check the fuel injectors.
Checking the sensor	Check the engine coolant temperature (ECT) sensor. Use a scan tool to compare the coolant temperature to the ambient temperature when the engine is cold. If the coolant temperature is 5 degrees higher or lower than the ambient temperature when the engine is cold, check the coolant circuit or the sensor itself for high electrical resistance. Turn ignition on with engine off. Using a scan tool, determine actual fuel rail pressure (FRP). FRP sensor signal voltage should be approximately 0.5 V. If not, check for high resistance in FRP sensor circuit or FRP sensor itself.
Checking the air intake system	Check for obstructions in the air filter or air intake ducts. Check for obstructions to the air flow in the turbocharger charge air cooler. Check if there are any obstructions to the air flow in the intake manifold. Check for air leaks in the charge air cooler. Check for leaks in the air ducts between the turbocharger and the intake manifold.
Checking the mechanical part of the engine	Check if there is an error in the selection of the main engine parts, such as the camshaft, heads, pistons, etc. Check to see if too much oil is entering the combustion chamber.

Malfunction Indicator Lamp (MIL) Not On

Description of the scheme

The fault indicator light must be permanently lit when the ignition switch is turned on and the engine is not running. The system voltage is applied to the indicator lamp, and the instrument panel serves as a conductor for grounding. After starting the engine, the instrument panel turns off the fault indicator light. If there is a failure in the engine management system, the ECM controller sends a message via the high-speed GMLAN network to the body control module with a request for a fault indicator light. The body control module then sends a message to the dashboard via the low-speed GMLAN network requesting that the fault indicator light is turned on.

Description of the test

The number below refers to the stage number from the diagnostic chart.

If other functions of the instrument panel are impaired, it is necessary to check the fuse or the presence of voltage supplied to the instrument panel and its grounding.

Malfunction Indicator Lamp (MIL) Not On

Step	Operation	Values	Yes	No
1	Have you performed a diagnostic system check?	-	Jump to operations 2	Go to item "Checking the diagnostic system".
2	Check the operation of the entire instrument panel. Are all other dashboard functions working properly?	-	Jump to operations 3	Jump to section 9E, Instrumentation/Driver Information
3	Replace the instrument panel. Has the replacement been made?	-	Jump to operations 4	-
4	Turn on the system to check the repair results. Has the problem been resolved?	-	The system is normal	Jump to operations 2