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

1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle.
2. If equipped with 2 wheel drive (2WD) perform the following steps, if equipped with 4 wheel drive (4WD) proceed to step 5.
3. Remove the connector position assurance (CPA) retainer (2).
4. Disconnect the HO2S electrical connector (3) from the engine wiring harness electrical connector (5).



5. Remove the connector position assurance (CPA) retainer (2).
6. Disconnect the HO2S electrical connector (4) from the engine wiring harness electrical connector (3).

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




7. 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 sensor is to be reinstalled, the threads must have anti-seize compound applied before the reinstallation.

Caution: Refer to Fastener Caution in the Preface section.




1. If reinstalling the old sensor, coat the threads with anti-seize compound GM P/N 12377953, or equivalent.
2. Install the HO2S (4).

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




3. If equipped with 4WD perform the following steps, if equipped with 2WD proceed to step 6.
4. Connect the HO2S electrical connector (4) to the engine wiring harness electrical connector (3).
5. Install the CPA retainer (2).



6. Connect the HO2S electrical connector (3) to the engine wiring harness electrical connector (5).
7. Install the CPA retainer (2).
8. Lower the vehicle.