Oxygen, Lambda Sensor Exhaust Oxygen Sensor (O2 Sensor) Measures oxygen in the exhaust so the ECU can correct the air-fuel mixture BAPMIC "BACB51-741015" - Not availableCADILLAC - XTS, CTS, STS, SRX; CHEVROLET - Camaro, Trailblazer; BUICK - Enclave