Possible causes – Engine Control Module (ECM) may be faulty– ECM harness power supply circuit is open or shorted– ECM harness ground circuit is open or shorted Tech notes Check the ECM fuse, if fuse is OK try erasing the

Possible causes – Engine Control Module (ECM) not programed– ECM program– Faulty ECM– Wrong ECM Symptoms – Engine Light ON (or Service Engine Soon Warning Light) P0602 MAZDA Description This diagnostic trouble code (DTC) indicates a programming error within the

Possible causes – Engine Control Module (ECM) Programming error– Odometer not programmed to ECM– Faulty or wrong ECM Tech notes If a new ECM/PCM is installed in a vehicle, the mileage has to be reprogrammed to the new ECM/PCM When

Possible causes – Engine Control Module (ECM) Programming error– Vehicle Identification Number (VIN) not programmed to ECM– Faulty or wrong ECM Tech notes If a new ECM is installed in a vehicle, the Vehicle Identification Number (VIN) has to be

Possible causes – Excessive resistance in the circuit– Low or no fuel– Wiring harness connector of the fuel pressure sensor– Fuel Rail Pressure Sensor– Fuel Pump Symptoms – Engine Light ON (or Service Engine Soon Warning Light)– Engine will not

Possible causes – Exhaust Gas Recirculation (EGR) volume control valve stuck closed– Faulty Exhaust Gas Recirculation (EGR) volume control solenoid valve– Faulty EGR Valve– Faulty EGR temperature sensor and circuit– Exhaust Gas Recirculation (EGR) solenoid valve harness is open or

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 Barometric Pressure (BARO) sensor– Faulty Manifold Absolute Pressure (MAP) sensor– Manifold Absolute Pressure sensor harness open or shorted to ground– Manifold Absolute Pressure sensor circuit poor electrical connection– Engine mechanical problems When is the code detected?

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 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? Vehicle speed over 35 MPH and down to 0 MPH 5 times-No change in brake switch

Possible causes – Faulty Brake Switch– Brake Switch harness is open or shorted– Brake Switch circuit poor electrical connection– Misadjusted Brake Switch When is the code detected? The stop light switch does not turn off even once vehicle is driven.

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,

Possible causes – Faulty Brake Switch– Misadjusted brake switch– Brake Switch harness is open or shorted– Brake Switch circuit poor electrical connection When is the code detected? The P0571 codes is set when the stop light switch does not turn

Possible causes – Faulty Camshaft Position Sensor– Camshaft Position Sensor harness is open or shorted– Camshaft Position Sensor circuit poor electrical connection– Faulty starter motor– Starting system circuit– Dead (Weak) battery Tech notes Sometimes and in some models, low battery

Possible causes – Faulty Camshaft Position Sensor– Camshaft Position Sensor harness is open or shorted– Camshaft Position Sensor circuit poor electrical connection– Faulty starter motor– Starting system circuit– Dead (Weak) battery Tech notes Sometimes and in some models, low battery

Possible causes – Faulty Camshaft Position Sensor– Camshaft Position Sensor harness is open or shorted– Camshaft Position Sensor circuit poor electrical connection– Faulty starter motor– Starting system circuit– Dead (Weak) battery Tech notes Sometimes and in some models, low battery

Possible causes – Faulty Camshaft Position Sensor– Camshaft Position Sensor harness is open or shorted– Camshaft Position Sensor circuit poor electrical connection– Faulty starter motor– Starting system circuit– Dead (Weak) battery Tech notes Sometimes and in some models, low battery