Oxygen, Lambda Sensor Exhaust Oxygen Sensor (O2 Sensor) Measures oxygen in the exhaust so the ECU can correct the air-fuel mixture NTK "0017" - Not availableCHEVROLET - Lacetti, Nubira, Aveo, Kalos, Optra; DAEWOO - Lacetti, Nubira; AUDI - A6, A4