Oxygen, Lambda Sensor Exhaust Oxygen Sensor (O2 Sensor) Measures oxygen in the exhaust so the ECU can correct the air-fuel mixture Gebe "9 7140 1" - Not availablePEUGEOT - 206, Partner, 306, 307, 406; CITROËN - C5, Xsara; FIAT - Ducato, Ulysse