Buick/Chevrolet Oxygen Sensor 12637338/12663317 Onix/Cruze/Malibu/Sail Replacement

When your Buick or Chevrolet shows rough idle, weak acceleration, noticeably higher fuel consumption, or the dashboard lights up “Check Engine,” this typically indicates aging or failure of the oxygen sensor, unable to accurately monitor exhaust oxygen content. In normal operation, the sensor provides real-time feedback to the ECU to adjust the air-fuel ratio, helping the engine maintain optimal burning efficiency and power output while saving fuel. This product is compatible with OEM numbers 12637338, 12663317, 12701634, and 855568, suitable for Buick Enclave, Chevrolet Cruze, Malibu, Sail etc. Installation requires a cold engine, use a dedicated socket to avoid damaging threads or wiring, and ensure connectors are fully locked.