Oxygen, Lambda Sensor Exhaust Oxygen Sensor (O2 Sensor) Measures oxygen in the exhaust so the ECU can correct the air-fuel mixture Triscan "8845 28009" - Not availablePEUGEOT - 306, 106, 406, 207, 308; CITROËN - Xantia, Xsara; DS - DS 3, DS 4