雪佛兰别克 GMC 凯迪拉克下游后氧传感器 12637338 / 234-8051，AIUSLN 外批好货

Chevrolet, Buick, GMC, Cadillac downstream rear oxygen sensor 12637338 / 234-8051, AIUSLN bulk good; installed behind the catalytic converter in the exhaust system; main function is to monitor exhaust oxygen content and feed ECU to adjust air-fuel ratio to meet emissions standards and fuel economy. OEM number 12637338; compatible with 0258010361, 12663317, 12701634, 24108641, 26226026; applicable to Cadillac, Chevrolet, Buick, GMC and other models. Installation difficulty: medium; estimated labor 0.5-1 hour; note that sensor position may require a special socket due to undercarriage layout.