Removal (HO2S 1)

WARNING: This page is about a different car, the 2003 Oldsmobile Bravada, 2003 GMC Envoy XL, 2003 GMC Envoy, and 2003 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.

Turn ignition off. 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 below 120°F (48°C). Excessive removal force may damage threads in exhaust manifold.
Disconnect harness connector from HO2S 1. Carefully remove HO2S 1 from exhaust manifold using Oxygen Sensor Tool (J-39194-C).

Fig 1: Locating HO2S 1

Courtesy of GENERAL MOTORS CORP.

Fig 2: Locating HO2S 2

Courtesy of GENERAL MOTORS CORP.