Oxygen, Lambda Sensor Exhaust Oxygen Sensor (O2 Sensor) Measures oxygen in the exhaust so the ECU can correct the air-fuel mixture Metzger "0893213" - Not availableCITROËN - C5, Xsara, C4, Saxo, C3; PEUGEOT - 206, 306; FIAT - Ducato, Ulysse