Heated Oxygen Sensor Replacement Pre-Catalyst

Notice: Refer to Heated Oxygen Sensor Resistance Learn Reset Notice in the Preface section.

Notice: The oxygen sensor uses a permanently attached pigtail and connector. Do not remove the pigtail from the oxygen sensor. Damage to or removal of the pigtail connector could affect proper operation of the oxygen sensor.

Notice: The use of excessive force may damage the threads in the exhaust manifold/pipe.

Important: The in-line connector and louvered end must be kept clear of grease, dirt or other contaminants. Avoid using cleaning solvents of any type. DO NOT drop or roughly handle the oxygen sensor (O2S).

Important: The O2S may be difficult to remove when the engine temperature is less than 48°C (120°F).




1. Remove the exhaust manifold heat shield. Refer to Exhaust Manifold Replacement in Engine Exhaust.



2. Disconnect the O2S harness connector.
3. Remove the O2S.

Important: A special anti-seize compound is used on the O2S 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 will have the compound applied to the threads. If a sensor is removed and is to be reinstalled, the threads must have an anti-seize compound applied before installation.

1. Coat the threads of the O2S with anti-seize compound, if necessary.




Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

2. Install the O2S.

Tighten
Tighten the O2S to 30 N·m (22 lb ft).

3. Connect the O2S harness connector.



4. Install the exhaust manifold heat shield. Refer to Exhaust Manifold Replacement in Engine Exhaust.

Heated Oxygen Sensor Replacement Post-Catalyst

Tools Required

J 39194-C Oxygen Sensor Wrench

Notice: Refer to Heated Oxygen Sensor Resistance Learn Reset Notice in the Preface section.




1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
2. Note the routing of the heated oxygen sensor (HO2S) electrical harness (2).
3. Disconnect the HO2S electrical connector in the engine compartment (1).



4. Using the J 39194 carefully remove the HO2S.

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

5. Lower the HO2S electrical harness away from the underbody (1).

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 equivalent.
2. Carefully install the HO2S to the pipe (1).

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).





Notice: Refer to Heated Oxygen Sensor Resistance Learn Reset Notice in the Preface section.

4. Install the HO2S electrical harness into position as noted before removal (2).



5. Connect the HO2S electrical connector (1).
6. Lower the vehicle.