Oxygen, Lambda Sensor Exhaust Oxygen Sensor (O2 Sensor) Measures oxygen in the exhaust so the ECU can correct the air-fuel mixture Delphi "ES20378-12B1" - Not availableAUDI - A3, A4, A6, A8, Q7; VW - Golf, EOS; SEAT - Leon, Altea; SKODA - Octavia