Oxygen, Lambda Sensor Exhaust Oxygen Sensor (O2 Sensor) Measures oxygen in the exhaust so the ECU can correct the air-fuel mixture LUCAS "LEB703" - Not availableCITROËN - Xsara, Xantia, Berlingo, C5, Saxo; PEUGEOT - 306, 406, 206, Partner, 106, 307