Possible causes – A/C system low or over charge with refrigerant– Faulty A/C refrigerant pressure sensor– Cooling fans in-operative– A/C refrigerant pressure sensor circuit open or shorted– A/C refrigerant pressure sensor circuit poor electrical connection When is the code detected?

Possible causes – A/C system low or over charge with refrigerant– Faulty A/C refrigerant pressure sensor– Cooling fans in-operative– A/C refrigerant pressure sensor circuit open or shorted– A/C refrigerant pressure sensor circuit poor electrical connection When is the code detected?

Possible causes – Battery charge– Faulty Generator– Generator harness is open or shorted– Generator circuit poor electrical connection– Engine Control Module (ECM) controlled generator– Faulty ECM Tech notes If the battery is OK then the alternator is more than likely

Possible causes – Battery charge– Faulty Generator– Generator harness is open or shorted– Generator circuit poor electrical connection– Engine Control Module (ECM) controlled generator– Faulty ECM Tech notes The ECM/PCM is detecting a high turn-on voltage at times. Possible causes

Possible causes – Battery defective– Loose or missing alternator drive belt– Faulty alternator– Open or short system voltage circuit Tech notes Higher than expected voltage problems are most likely caused by bad voltage regulator. The voltage regulator is part of

Possible causes – Dirty Oil– Engine mechanical problems– Timing belt jumped teeth Symptoms – Engine Light ON (or Service Engine Soon Warning Light)

Possible causes – Dirty Oil– Engine mechanical problems– Timing belt jumped teeth Symptoms – Engine Light ON (or Service Engine Soon Warning Light)

Possible causes – Dirty Oil– Engine mechanical problems– Timing belt jumped teeth Symptoms – Engine Light ON (or Service Engine Soon Warning Light)

Possible causes – Dirty Oil– Engine mechanical problems– Timing belt jumped teeth Symptoms – Engine Light ON (or Service Engine Soon Warning Light)

Possible causes – Dirty Oil– Faulty Exhaust valve timing control solenoid valve– Exhaust valve timing control solenoid valve harness is open or shorted– Exhaust valve timing control solenoid valve circuit poor electrical connection– Faulty Crankshaft position sensor (POS)– Faulty Camshaft

Possible causes – Drive-by-wire control system malfunction– Throttle actuator malfunction– Throttle valve malfunction– PCM malfunction Tech notes Dirty or clogged throttle body can triggered the P0638 code. Before replacing any parts try cleaning the throttle body and reset the engine

Possible causes – EGR solenoid valve harness is open or shorted– EGR solenoid valve circuit poor electrical connection– EGR volume control valve stuck closed– Dead (Weak) battery– Faulty EGR temperature sensor and circuit– Faulty EGR Valve– EGR passage clogged– Exhaust

Possible causes – Engine mechanical problems– Incorrect timing chain– Stretched timing chain– Failed camshaft actuator or actuator solenoid When is the code detected? The ECM detects that both camshafts on either bank of the engine are mis-aligned with the crankshaft

Possible causes – Engine mechanical problems– Incorrect timing chain– Stretched timing chain– Failed camshaft actuator or actuator solenoid When is the code detected? The ECM detects that both camshafts on either bank of the engine are mis-aligned with the crankshaft

Possible causes – Faulty Air Conditioning Clutch Relay– Air Conditioning Clutch Relay harness is open or shorted– Air Conditioning Clutch Relay circuit poor electrical connection When is the code detected? Code P0646 may be stored if an open or short

Possible causes – Faulty Air Conditioning Clutch Relay– Air Conditioning Clutch Relay harness is open or shorted– Air Conditioning Clutch Relay circuit poor electrical connection When is the code detected? Code P0647 may be stored if an open or short

Possible causes – Faulty Air Conditioning Clutch Relay– Air Conditioning Clutch Relay harness is open or shorted– Air Conditioning Clutch Relay circuit poor electrical connection When is the code detected? The P0645 code is stored if an open or short

Possible causes – Faulty battery– Generator drive belt missing or loose– Faulty Generator– Generator harness is open or shorted– Generator circuit poor electrical connection Tech notes If the battery is OK then the alternator is more than likely the problem.

Possible causes – Faulty Brake Switch– Brake Switch harness is open or shorted– Brake Switch circuit poor electrical connection When is the code detected? The P0573 codes is set when the stop light switch signal is too high. Symptoms –

Possible causes – Faulty Brake Switch– Misadjusted Brake Switch– Brake Switch harness is open or shorted– Brake Switch circuit poor electrical connection Tech notes Check if the stop light works with the brake pedal, if the brake lights are inoperative,