Oxygen, Lambda Sensor Exhaust Oxygen Sensor (O2 Sensor) Measures oxygen in the exhaust so the ECU can correct the air-fuel mixture FAE "75125" - Not availableMERCEDES-BENZ - C-Class, E-Class, GLC, SLC, SLK; BMW - X3, 3, 5, 1, 4, 6, X5, X1, X6