Oxygen, Lambda Sensor Exhaust Oxygen Sensor (O2 Sensor) Measures oxygen in the exhaust so the ECU can correct the air-fuel mixture FEBI Bilstein "24229" - Not availableBMW - 3, 5 (E39, WB), Z3, 7, 8, X5, Z4, X3, Z8; ALPINA - Roadster V8