Possible causes – Air Injection Pump Relay harness is open or shorted– Air Injection Pump Relay circuit poor electrical connection– Faulty Air Injection Pump Relay Symptoms – Engine Light ON (or Service Engine Soon Warning Light)

Possible causes – Check air duct intake for damage– Check engine for vacuum leaks– Faulty Mass Air Flow (MAF) Sensor Symptoms – Engine Light ON (or Service Engine Soon Warning Light)

Possible causes – Check Anti-Theft system for fault

Possible causes – Check Vacuum Diaphragm and hoses for Boost Pressure Regulator Valve– Check wastegate bypass regulator valve Symptoms – Engine Light ON (or Service Engine Soon Warning Light)

Possible causes – EGR Valve harness is open or shorted– EGR Valve circuit poor electrical connection– Faulty EGR Valve Symptoms – Engine Light ON (or Service Engine Soon Warning Light)

Possible causes – Engine low on coolant– Faulty thermostat– Faulty Engine Coolant Temperature (ECT) Sensor– Engine Coolant Temperature Sensor harness is open or shorted– Engine Coolant Temperature Sensor circuit poor electrical connection Tech notes 2004 Volkswagen Jetta User Submitted Video

Possible causes – Engine low on coolant– Faulty thermostat– Faulty Engine Coolant Temperature (ECT) Sensor– Engine Coolant Temperature Sensor harness is open or shorted– Engine Coolant Temperature Sensor circuit poor electrical connection Tech notes 2004 Volkswagen Jetta User Submitted Video

Possible causes – Engine mechnical condition– Fuel system malfunction– Ignition system malfunction– Faulty oxygen sensor Tech notes There is a service bulletin for the following Volkswagen vehicles: Volkswagen Eos 2006-2007Volkswagen GTI 2006-2007Volkswagen Jetta 2005-2007Volkswagen Passat 2006-2007Volkswagen Passat Wagon 2006-2007Volkswagen Factory

Possible causes – Faulty Camshaft Actuator– Camshaft Actuator harness is open or shorted– Camshaft Actuator circuit poor electrical connection Symptoms – Engine Light ON (or Service Engine Soon Warning Light)

Possible causes – Faulty Camshaft Actuator– Camshaft Actuator harness is open or shorted– Camshaft Actuator circuit poor electrical connection Symptoms – Engine Light ON (or Service Engine Soon Warning Light)

Possible causes – Faulty Camshaft Actuator– Camshaft Actuator harness is open or shorted– Camshaft Actuator circuit poor electrical connection Symptoms – Engine Light ON (or Service Engine Soon Warning Light)

Possible causes – Faulty Catalyst Temperature Sensor– Catalyst Temperature Sensor harness is open or shorted– Catalyst Temperature Sensor circuit poor electrical connection Symptoms – Engine Light ON (or Service Engine Soon Warning Light)

Possible causes – Faulty Closed Throttle Position Switch– Closed Throttle Position Switch harness is open or shorted– Closed Throttle Position Switch circuit poor electrical connection Symptoms – Engine Light ON (or Service Engine Soon Warning Light)

Possible causes – Faulty Coolant Flow Control Valve Position Sensor– Coolant Flow Control Valve Position Sensor harness is open or shorted– Coolant Flow Control Valve Position Sensor circuit poor electrical connection Symptoms – Engine Light ON (or Service Engine Soon

Possible causes – Faulty EVAP Canister Purge Regulator Valve– EVAP Canister Purge Regulator Valve harness is open or shorted– EVAP Canister Purge Regulator Valve circuit poor electrical connection Symptoms – Engine Light ON (or Service Engine Soon Warning Light) P1426

Possible causes – Faulty Exhaust Gas Temperature Sensor– Exhaust Gas Temperature Sensor harness is open or shorted– Exhaust Gas Temperature Sensor circuit poor electrical connection Symptoms – Engine Light ON (or Service Engine Soon Warning Light)

Possible causes – Faulty Front Heated Oxygen Sensor Bank 1– Front Heated Oxygen Sensor Bank 1 harness is open or shorted– Front Heated Oxygen Sensor Bank 1 circuit poor electrical connection– Inappropriate fuel pressure– Faulty fuel injectors– Intake air leaks

Possible causes – Faulty Front Heated Oxygen Sensor Bank 1– Front Heated Oxygen Sensor Bank 1 harness is open or shorted– Front Heated Oxygen Sensor Bank 1 circuit poor electrical connection– Inappropriate fuel pressure– Faulty fuel injectors– Intake air leaks

Possible causes – Faulty fuel pressure control valve– Fuel pressure control valve harness is open or shorted– Fuel pressure control valve circuit poor electrical connection Symptoms – Engine Light ON (or Service Engine Soon Warning Light)

Possible causes – Faulty fuel pressure control valve– Fuel pressure control valve harness is short to ground– Fuel pressure control valve circuit poor electrical connection Symptoms – Engine Light ON (or Service Engine Soon Warning Light)