Oxygen, Lambda Sensor Exhaust Oxygen Sensor (O2 Sensor) Measures oxygen in the exhaust so the ECU can correct the air-fuel mixture KW "498 581" - Not availableBMW - 3 (F30, F80), 5, 4 (F32, F33, F82), 1, 2, X5, X3, X1, X4, Z4 Roadster, I3, 6, 7, X6