Oxygen, Lambda Sensor Exhaust Oxygen Sensor (O2 Sensor) Measures oxygen in the exhaust so the ECU can correct the air-fuel mixture Delphi "ES21508-12B1" - Not availableBMW - 5 (F90, G30), 3, 4, X3, X4, 2, Z4, 6 Gran Turismo, 7 (G11, G12), X5