Caution: Refer to Heated Oxygen and Oxygen Sensor Caution in the Preface section.

1. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle.
2. Disconnect the connector position assurance (CPA) retainer.
3. Disconnect the engine wiring harness electrical connector (1) from the HO2S pigtail electrical connector.
4. Remove the HO2S pigtail electrical connector clip (2) from the frame.



5. Remove the HO2S (4).

Note: A special anti-seize compound is used on the HO2S threads. The compound consists of liquid graphite and glass beads. The graphite tends to burn away, but the glass beads remain, making the sensor easier to remove. New, or service replacement sensors already have the compound applied to the threads. If the sensor is removed from an exhaust component and if for any reason the old sensor is to be reinstalled, the threads must have anti-seize compound applied before the reinstallation.

1. If reinstalling the old HO2S, coat the threads with anti-seize compound GM P/N 12377953, or equivalent.

Caution: Refer to Fastener Caution in the Preface section.

2. Install the HO2S (4).

Tighten
Tighten the sensor to 42 N·m (31 lb ft).




3. Install the HO2S pigtail electrical connector clip (2) to the frame.
4. Connect the engine wiring harness electrical connector (1) to the HO2S pigtail electrical connector.
5. Connect the CPA retainer.
6. Lower the vehicle.