Oxygen, Lambda Sensor Exhaust Oxygen Sensor (O2 Sensor) Measures oxygen in the exhaust so the ECU can correct the air-fuel mixture BAPMIC "BF0426110418" - Not availableBMW - 3, 5, 6, 1, 7; AUDI - A4, A3; PORSCHE - 911; ALFA ROMEO - 156, 159