Oxygen Sensors: Notes

WARNING: This page is about a different car, the 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, 2002 Chevrolet Silverado, and 2002 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: Do not repair wiring, connector or terminals on oxygen sensor. Replace oxygen sensor if pigtail wiring, connector or terminal is damaged. Oxygen sensors are equipped with a permanent pigtail which must remain intact when removing sensor.

NOTE: Ensure oxygen sensor is free of contaminants. DO NOT use cleaning solvents of any type. Oxygen sensor may be difficult to remove when engine temperature is less than 120°F (48°C). Excessive removal force may damage threads in exhaust pipe.

NOTE: Front Heated Oxygen Sensors (HO2S11 and HO2S21) are located in the exhaust pipes, below the respective exhaust manifold. See Figure. 3500 HD models are equipped only with HO2S11 and HO2S21. On all models except 3500 HD, Rear Heated Oxygen Sensors (HO2S12 and HO2S22) are mounted in the exhaust pipes, behind the respective catalytic converter. On some 8.1L models, it may be necessary to lower the exhaust system to gain sufficient access to a HO2S and/or HO2S harness connector.