Possible causes – Dirty Oil– Engine mechanical problems– Faulty camshaft position sensor– Faulty crankshaft position sensor– Timing belt jumped Tech notes There is a factory service bulletin for the following Hummer models: 2004-2009 Hummer H32004-2009 Hummer H3 Factory Service Bulletin

Possible causes – Dirty Oil– Low engine oil level– Faulty Exhaust Camshaft Position Actuator Solenoid– Exhaust Camshaft Position Actuator Solenoid harness is open or shorted– Exhaust Camshaft Position Actuator Solenoid circuit poor electrical connection– Faulty Engine Control Module (ECM) Tech

Possible causes – Faulty front heated oxygen sensor– Ignition misfiring– Faulty fuel injectors– Exhaust gas leaks– Incorrect fuel pressure – Faulty Mass Air Flow (MAF) sensor When is the code detected? – Fuel injection system does not operate properly.– The

Possible causes – Faulty Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1 circuit– Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1 circuit fuse– Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1 circuit open shorted to ground– Heated Oxygen Sensor (H2OS)

Possible causes – Faulty Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1– Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1 circuit fuse– Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1 circuit open shorted to ground– Heated Oxygen Sensor (H2OS) Bank

Possible causes – Faulty Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2– Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2 circuit fuse– Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2 circuit open shorted to ground– Heated Oxygen Sensor (H2OS) Bank

Possible causes – Faulty Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2– Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2 fuse– Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2 harness is open or shorted– Heated Oxygen Sensor (H2OS) Bank 1

Possible causes – Faulty Manifold Absolute Pressure sensor– Manifold Absolute Pressure harness is open or shorted– Manifold Absolute Pressure sensor circuit poor electrical connection– Faulty Engine Control Module (ECM) When is the code detected? An excessively low or high voltage

Possible causes – Faulty mass air flow sensor– Intake air leaks– Dirty mass air flow sensor– Dirty mass air filter– Mass air flow sensor harness is open or shorted– Mass air flow sensor circuit poor electrical connection Tech notes Before

Possible causes – Faulty mass air flow sensor– Intake air leaks– Dirty mass air flow sensor– Dirty mass air filter– Mass air flow sensor harness is open or shorted– Mass air flow sensor circuit poor electrical connection Tech notes Before

Possible causes – Faulty mass air flow sensor– Intake air leaks– Dirty mass air flow sensor– Dirty mass air filter– Mass air flow sensor harness is open or shorted– Mass air flow sensor circuit poor electrical connection Tech notes Before

Possible causes – Faulty mass air flow sensor– Intake air leaks– Dirty mass air flow sensor– Dirty mass air filter– Mass air flow sensor harness is open or shorted– Mass air flow sensor circuit poor electrical connection Tech notes Before

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

Possible causes – Faulty Reverse Inhibit Solenoid– Reverse Inhibit Solenoid harness is open or shorted– Reverse Inhibit Solenoid circuit poor electrical connection When is the code detected? When the Reverse Inhibit solenoid energizes, the operator can shift the transmission into

Possible causes – Faulty Skip Shift Lamp– Skip Shift Lamp harness is open or shorted– Skip Shift Lamp circuit poor electrical connection When is the code detected? When the Powertrain Control Module (PCM) commands the control circuit to a component

Possible causes – Faulty Skip Shift Solenoid– Skip Shift Solenoid harness is open or shorted– Skip Shift Solenoid circuit poor electrical connection Symptoms – Engine Light ON (or Service Engine Soon Warning Light) P0803 HUMMER Description An ignition voltage is

Possible causes – Faulty spark plug (s) – Faulty ignition coil (s) – Clogged or faulty fuel injector (s)– Intake air leak– Fuel injectors harness is open or shorted– Fuel Injectors circuit poor electrical connection– Ignition coils harness is open

Possible causes – Faulty spark plug 1– Clogged or faulty fuel injector 1– Faulty ignition coil 1– Fuel injector 1 harness is open or shorted– Fuel injector 1 circuit poor electrical connection– Ignition coil 1 harness is open or shorted–

Possible causes – Faulty spark plug 2– Clogged or faulty fuel injector 2– Faulty ignition coil 2– Fuel injector 2 harness is open or shorted– Fuel injector 2 circuit poor electrical connection– Ignition coil 2 harness is open or shorted–

Possible causes – Faulty spark plug 3– Clogged or faulty fuel injector 3– Faulty ignition coil 3– Fuel injector 3 harness is open or shorted– Fuel injector 3 circuit poor electrical connection– Ignition coil 3 harness is open or shorted–