For 1990-2009 cars

#### Tools Required

J 39194-C Oxygen Sensor Wrench

### Removal Procedure

1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .
2. Remove the wheel drive shaft heat shield. Refer to Wheel Drive Shaft Heat Shield Replacement .
3. Note the routing of the heated oxygen sensor (HO2S) electrical harness.
4. Disconnect the HO2S electrical connector (2), in the engine compartment.
5. Carefully bend the edge of the channel on the LH side of the exhaust heat shield outboard, just enough to release the HO2S electrical harness (1).

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

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

6. Using the J 39194 carefully remove the HO2S.
7. Lower the HO2S electrical harness away from the underbody.

### Installation Procedure

Important: A special anti-seize compound is used on the HO2S threads. The compound consists of a liquid graphite and glass beads. The graphite will burn away but the glass beads will remain, making the sensor easier to remove. New or service sensors already have the compound applied to the threads. If the sensor is removed and is to be reinstalled, the threads must be coated with an anti-seize compound before reinstallation.

1. If reinstalling the old HO2S, coat the threads with anti-seize compound, GM P/N 12377953 or Saturn P/N 24185279, or equivalent.
2. Carefully install the HO2S to the pipe.

Notice: Refer to Component Fastener Tightening Notice in the Preface section.

3. Using the J 39194 or equivalent, tighten the HO2S.

Tighten
Tighten the HO2S to 41 N·m (30 lb ft).

4. Install the HO2S electrical harness into position as noted before removal.

Important: Use care when securing the HO2S electrical harness into the channel on the exhaust heat shield, to not pinch the wires.

5. Carefully bend the edge of the channel (1) on the LH side of the exhaust heat shield inboard, just enough to secure the HO2S electrical harness in the channel.
6. Connect the HO2S electrical connector (2).
7. Install the wheel drive shaft heat shield. Refer to Wheel Drive Shaft Heat Shield Replacement .
8. Lower the vehicle.