Oxygen, Lambda Sensor Exhaust Oxygen Sensor (O2 Sensor) Measures oxygen in the exhaust so the ECU can correct the air-fuel mixture NTK "1813" - Not availableCITROËN - Xsara, C3, Saxo, C2, Nemo; PEUGEOT - 206, 207; FIAT - Fiorino, Qubo