Oxygen, Lambda Sensor Exhaust Oxygen Sensor (O2 Sensor) Measures oxygen in the exhaust so the ECU can correct the air-fuel mixture FAE "77279" - Not availableBMW - 3 (E30, E46, E91), 5, 1, 6, 7 (F01, F02, F03), X6, X5, Z4, X3, X1; AUDI - A4, TT, A8