Oxygen, Lambda Sensor Exhaust Oxygen Sensor (O2 Sensor) Measures oxygen in the exhaust so the ECU can correct the air-fuel mixture Metzger "0893098" - Not availableBMW - 3, 5, 1, 6, 7; AUDI - A4, A6; MAZDA - Premacy, 323; ALFA ROMEO - 156, 159