Possible causes – Low fuel pressure– Large vacuum leak on engine– Faulty Mass Air Flow (MAF) sensor– Faulty Ignition– Faulty fuel injector Symptoms – Engine Light ON (or Service Engine Soon Warning Light)

Possible causes – Low fuel pressure– Large vacuum leak on engine– Faulty Mass Air Flow (MAF) sensor– Faulty Ignition– Faulty fuel injector Symptoms – Engine Light ON (or Service Engine Soon Warning Light)

Possible causes – Oxygen sensor harness is open or shorted– Oxygen sensor circuit poor electrical connection– Exhaust system leak– Faulty front or rear (pre-cat or downstream) sxygen sensor Symptoms – Engine Light ON (or Service Engine Soon Warning Light)

Possible causes – Pre cat or downstream post cat o2 sensor harness is open or shorted– Pre cat or downstream post cat o2 sensor circuit poor electrical connection– Exhaust system leak– Faulty pre cat or downstream post cat o2 sensor

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

Symptoms – Engine Light ON (or Service Engine Soon Warning Light) P1554 BMW Description Engine position system A performance bank 1

Symptoms – Engine Light ON (or Service Engine Soon Warning Light)

Symptoms – Engine Light ON (or Service Engine Soon Warning Light)