Oxygen, Lambda Sensor Exhaust Oxygen Sensor (O2 Sensor) Measures oxygen in the exhaust so the ECU can correct the air-fuel mixture FAE "77409" - Not availableBMW - 3, 5 (E39, WB), 6, 7 (E65, E66, E67), X5, X6, 1, X3, X1, Z4; ROLLS-ROYCE - Phantom