Oxygen, Lambda Sensor Exhaust Oxygen Sensor (O2 Sensor) Measures oxygen in the exhaust so the ECU can correct the air-fuel mixture Mobiletron "OS-B537" - Not availableBMW - 5, 3, X3, 7 (F01, F02, F03), X5, X6, 1, 6, X1; AUDI - A6