Oxygen, Lambda Sensor Exhaust Oxygen Sensor (O2 Sensor) Measures oxygen in the exhaust so the ECU can correct the air-fuel mixture StartVOLT "VS-OS 2103" - Not availableAUDI - A3, A4, A5, A6, A8, S6, TT, A1, Q5, Q7, Q3; VW - Golf, Passat