Possible causes – Deterrent key not programmed to vheicle– Faulty Deterrent key– Fualty ignition switch– Poor electrical connection for Deterrent circuit components Symptoms – Engine Light ON (or Service Engine Soon Warning Light)– No or hard engine start situation P1648

Possible causes – Deterrent key not programmed to vheicle– Faulty Deterrent key– Fualty ignition switch– Poor electrical connection for Deterrent circuit components Symptoms – Engine Light ON (or Service Engine Soon Warning Light)– No or hard engine start situation P1677

Possible causes – Deterrent key not programmed to vheicle– Faulty Deterrent key– Fualty ignition switch– Poor electrical connection for Deterrent circuit components Symptoms – Engine Light ON (or Service Engine Soon Warning Light)– No or hard engine start situation P1678

Possible causes – Deterrent key not programmed to vheicle– Faulty Deterrent key– Fualty ignition switch– Poor electrical connection for Deterrent circuit components Symptoms – Engine Light ON (or Service Engine Soon Warning Light)– No or hard engine start situation P1679

Possible causes – Engine Control Module (ECM) programm error– Wrong Engine Control Module (ECM)– Faulty Engine Control Module (ECM) Tech notes This code means that there may be an internal problem with the Engine Control Module (ECM). Start by checking

Possible causes – Engine mechanical condition-Valve timing off– Cam sensor or crank sensor are loose on their mounting– Faulty camshaft position sensor– Faulty crankshaft position sensor Tech notes If this DTC started after recent internal engine repairs, inspect for proper

Possible causes – EVAP Canister Purge Solenoid harness is open or shorted – EVAP Canister Purge Solenoid circuit poor electrical connection – Faulty EVAP Canister Purge Solenoid Symptoms – Engine Light ON (or Service Engine Soon Warning Light) P1676 GMC

Possible causes – EVAP canister vent control solenoid harness is open or shorted – EVAP canister vent control solenoid circuit poor electrical connection – Faulty EVAP canister vent control solenoid Symptoms – Engine Light ON (or Service Engine Soon Warning

Possible causes – Exhaust leak – Improperly installed or loose Exhaust Gas Temperature (EGT) – Low engine compression – Corroed fuel injector – Water in the fuel system When is the code detected? The P2459 will set if the Engine

Possible causes – Faulty Accelerator Pedal Position Sensor– Accelerator Pedal Position Sensor harness is open or shorted– Accelerator Pedal Position Sensor circuit poor electrical connection When is the code detected? The Powertrain Control Module (PCM) detects that the difference between

Possible causes – Faulty Accelerator Pedal Position Sensor– Accelerator Pedal Position Sensor harness is open or shorted– Accelerator Pedal Position Sensor circuit poor electrical connection– Faulty Electric Throttle Control Actuator When is the code detected? The Engine Control Module (ECM)

Possible causes – Faulty AIR Pressure Sensor– AIR Pressure Sensor harness is open or shorted– AIR Pressure Sensor circuit poor electrical connection When is the code detected? The AIR Pressure Sensor is reporting a pressure greater than or less than

Possible causes – Faulty AIR Pressure Sensor– AIR Pressure Sensor harness is open or shorted– AIR Pressure Sensor circuit poor electrical connection When is the code detected? The AIR Pressure Sensor is reporting a pressure greater than or less than

Possible causes – Faulty AIR Pressure Sensor– AIR Pressure Sensor harness is open or shorted– AIR Pressure Sensor circuit poor electrical connection When is the code detected? The PCM has detected a high voltage condition on the AIR Pressure Sensor

Possible causes – Faulty AIR Pressure Sensor– AIR Pressure Sensor harness is open or shorted– AIR Pressure Sensor circuit poor electrical connection Symptoms – Engine Light ON (or Service Engine Soon Warning Light) P2432 GMC Description The Secondary Air Injection

Possible causes – Faulty Auxiliary Coolant Pump Relay– Blocked pump control passage– Faulty Auxiliary Coolant Pump– Auxiliary Coolant Pump harness is open or shorted– Auxiliary Coolant Pump circuit poor electrical connection When is the code detected? The Engine Control Module

Possible causes – Faulty Control Solenoid Valve Assembly– Control Solenoid Valve Assembly harness is open or shorted– Control Solenoid Valve Assembly circuit poor electrical connection When is the code detected? The Powertrain Control Module (PCM) commanded the Torque Converter Clutch

Possible causes – Faulty Cooling Fan Relay– Cooling Fan Relay harness is open or shorted– Cooling Fan Relay circuit poor electrical component Symptoms – Engine Light ON (or Service Engine Soon Warning Light) – Cooling Fan not working P1641 GMC

Possible causes – Faulty Cooling Fan Relay– Cooling Fan Relay harness is open or shorted– Cooling Fan Relay circuit poor electrical component Symptoms – Engine Light ON (or Service Engine Soon Warning Light) – Cooling Fan not working P1642 GMC

Possible causes – Faulty Crankshaft Position Sensor– Crankshaft Position Sensor harness is open or shorted– Crankshaft Position Sensor circuit poor electrical connection– Signal plate may be damage Symptoms – Engine Light ON (or Service Engine Soon Warning Light)– Lack/Loss of