Symptom Chart

Symptom (general)	Symptom (specific)	Possible causes	Action
Non-Start	Engine does not crank	Security system / Immobilizer engaged Engine control module (ECM) relay fault Battery discharged Starting system fault Engine seized	Check that the security system is disarmed. Check the ECM relay operation. Check the battery and starter systems. Refer to the electrical information. Check that the engine turns by hand.
	Engine cranks, but does not fire	Low/contaminated fuel Ignition system fault Fuel system fault Crankshaft position (CKP) sensor fault Engine control module (ECM) fault	Check the fuel level and condition. Check for DTCs indicating ignition, fuel or sensor faults. Rectify as necessary. Refer to the warranty policy and procedures information if an ECM is suspect.
	Engine cranks and fires, but will not start	Evaporative emissions purge valve fault Fuel system fault Spark plugs fouled/incorrect gap Ignition coil fault(s)	Check for DTCs indicating evaporative emissions, fuel or ignition system faults. Rectify as necessary.
Difficult to start	Difficult to start cold	Check coolant anti-freeze content Battery discharged Crankshaft position (CKP) sensor fault Fuel system fault Evaporative emissions purge valve fault	Check the coolant anti-freeze content. Check the battery condition and state of charge. Check for DTCs indicating a sensor, fuel system or evaporative emissions system fault. Rectify as necessary.
	Difficult to start hot	Injector leak Fuel system fault Fuel temperature sensor fault Intake air temperature (IAT) sensor fault Mass air flow (MAF) sensor fault Evaporative emissions purge valve fault Ignition system fault	Check for DTCs indicating an injector, fuel system or sensor fault. Check the evaporative emission and ignition systems. Rectify as necessary.
	Difficult to start after hot soak (vehicle standing after engine has reached operating temperature)	Injector leak Fuel system fault Fuel temperature sensor fault Intake air temperature (IAT) sensor fault Mass air flow (MAF) sensor fault Evaporative emissions purge valve fault Ignition system fault	Check for DTCs indicating an injector, fuel system or sensor fault. Check the evaporative emission and ignition systems. Rectify as necessary.
	Engine cranks too fast/slow	Battery discharged Starting system fault Compressions high/low	Check the battery condition and state of charge. Check the starter system. Refer to the electrical information. Check the engine compressions. Rectify as necessary.
Engine stalls	Engine stalls soon after start	Breather system disconnected/restricted Air filter restricted Fuel line fault Engine control module (ECM) relay fault Mass air flow (MAF) sensor fault Ignition system fault	Check the engine breather and intake systems. Check the fuel lines for leakage, etc. Check for DTCs indicating an ECM relay, sensor or ignition system fault. Rectify as necessary.
	Engine stalls on overrun	Engine control module (ECM) relay fault Throttle position (TP) sensors fault	Check for DTCs indicating an ECM relay or TP sensor fault. Rectify as necessary.
	Engine stalls at steady speed	Engine control module (ECM) relay fault Crankshaft position (CKP) sensor fault Throttle position (TP) sensors fault	Check for DTCs indicating an ECM relay or sensor fault. Rectify as necessary.
	Engine stalls with speed control enabled	Engine control module (ECM) relay fault	Check for DTCs indicating an ECM relay fault. Rectify as necessary.
	Engine stalls when maneuvering	Additional engine loads (power steering, air conditioning (A/C), etc.) Engine control module (ECM) relay fault Throttle position (TP) sensors fault Transmission malfunction Controller area network (CAN) malfunction	Check the accessory drive systems. Check for DTCs indicating an ECM relay, sensor, transmission or CAN fault. Rectify as necessary.
Poor driveability	Engine hesitates/poor acceleration	Fuel line fault Fuel pump fault Injector leak Fuel pressure fault Throttle position (TP) sensors fault Throttle motor fault Ignition system fault Heated oxygen sensor (HO2S) fault Transmission malfunction Restricted accelerator pedal travel (carpet, etc.) Accelerator pedal position (APP) sensor fault	Check the fuel lines and intake air system. Check for DTCs indicating a fuel pump or pressure fault. Check for DTCs indicating a TP sensor or motor fault. Check for DTCs indicating an ignition, sensor or transmission fault. Check the APP sensor for full movement, etc. Rectify as necessary.
	Engine backfires	Fuel pump fault Fuel line fault Mass air flow (MAF) sensor fault Heated oxygen sensor (HO2S) fault Ignition system fault Sticking variable valve timing (VVT) hub Accelerator pedal position (APP) sensor fault	Check the fuel pump and lines. Check for DTCs indicating a sensor, ignition or VVT fault. Rectify as necessary.
	Engine surges	Fuel pump fault Fuel line fault Mass air flow (MAF) sensor fault Throttle position (TP) sensors fault Throttle motor fault Ignition system fault	Check the fuel pump and lines. Check for DTCs indicating a sensor or ignition system fault. Rectify as necessary.
	Engine detonates/knocks	Fuel pump fault Fuel line fault Fuel quality Knock sensor (KS) / circuit malfunction Mass air flow (MAF) sensor fault Heated oxygen sensor (HO2S) fault Sticking variable valve timing (VVT) hub Barometric pressure (BARO) sensor malfunction (internal engine control module (ECM) fault)	Check the fuel pump and lines. Check the fuel for contamination and correct grade. Check for DTCs indicating a sensor, VVT or ECM fault. Rectify as necessary. Refer to the warranty policy and procedures information if an ECM is suspect.
	No throttle response	Accelerator pedal position (APP) sensor fault Throttle position (TP) sensors fault Throttle motor fault	Check for DTCs indicating a sensor or throttle motor fault. Rectify as necessary.
	Speed control inhibited or disabled	Default mode enabled Speed control switch(es) Throttle position (TP) sensors fault Controller area network (CAN) fault	Check the message center for default messages. Check for DTCs indicating a speed control, sensor or CAN fault. Rectify as necessary.
	Poor throttle response	Breather system disconnected/restricted Accelerator pedal position (APP) sensor fault Throttle position (TP) sensors fault Engine coolant temperature (ECT) sensor fault Mass air flow (MAF) sensor fault Transmission malfunction	Check the engine breather system. Check for DTCs indicating a sensor or transmission fault. Rectify as necessary.
	Engine defaults, warning light and messages. Refer to the owner handbook	Throttle position (TP) sensors fault Mass air flow (MAF) sensor fault Engine coolant temperature (ECT) sensor fault	Check for DTCs indicating a sensor fault. Rectify as necessary.