GM Service Manual Online
For 1990-2009 cars only

Tools Required

J 39194-B Heated Oxygen Sensor Wrench

Removal Procedure

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

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 heated oxygen sensor (HO2S).

Important: The HO2S may be difficult to remove when the engine temperature is less than 48°C (120°F)


    Object Number: 1642652  Size: SH
  1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .
  2. Remove the connector position assurance (CPA) retainer (2).
  3. Disconnect the engine harness electrical connector (1) from the HO2S.
  4. Remove the HO2S electrical connector clip from the heat shield.

  5. Object Number: 1645466  Size: SH
  6. Using the J 39194-B , remove the HO2S.

Installation Procedure

Important : A special anti-seize compound is used on the HO2S threads. The compound consists of 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 reinstallation.


    Object Number: 1645467  Size: SH
  1. If reinstalling the old HO2S, coat the threads with anti-seize compound GM P/N 12377953 or equivalent.
  2. 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.

  3. Using the J 39194-B , install the HO2S.
  4. Tighten
    Tighten the sensor to 41 N·m (30 lb ft).


    Object Number: 1642652  Size: SH
  5. Connect the engine harness electrical connector (1) to the HO2S.
  6. Install the CPA retainer (2).
  7. Install the HO2S electrical connector clip to the heat shield.
  8. Lower the vehicle.