Oxygen, Lambda Sensor Exhaust Oxygen Sensor (O2 Sensor) Measures oxygen in the exhaust so the ECU can correct the air-fuel mixture RECOFICIAL "CSL2445" - Not availableBMW - 3 (E91, E92, F30), 1, 5, 4 (F32, F82), X3, 6, X4, 2, X1