GM Service Manual Online
For 1990-2009 cars only

Notice: The Heated Oxygen Sensors each use a permanently attached pigtail and connector. This pigtail should not be removed from the heated oxygen sensor. Damage or removal of the pigtail or connector could affect proper operation of the heated oxygen sensor.

Removal Procedure

Important: Take care when handling the heated oxygen sensor. The in-line electrical connector and louvered end must be kept free of grease, dirt or other contaminants. Also, avoid using cleaning solvents of any type. Do not drop or roughly handle the heated oxygen sensor/catalyst monitor. A dropped sensor is a bad sensor.

Important: The heated oxygen sensor may be difficult to remove when engine temperature is below 48°C (120°F). Excessive force may damage threads in exhaust manifold or exhaust pipe.


    Object Number: 12669  Size: SH
  1. Raise the vehicle.

  2. Object Number: 17134  Size: SH
  3. Disconnect the electrical connector.
  4. Carefully back out the heated oxygen sensor(s).

Installation Procedure

Important: A special anti-seize compound is used on the heated oxygen sensor threads. The compound consists of graphite suspended in fluid 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 already have the compound applied to the threads. If a sensor is removed from an engine and if for any reason is to be reinstalled, the threads must have anti-seize compound applied before reinstallation.


    Object Number: 12669  Size: SH
  1. Coat threads of heated oxygen sensor/catalyst monitor with anti-seize compound P/N 5613695, or equivalent if necessary.

  2. Object Number: 17134  Size: SH
  3. Install Heated Oxygen Sensor(s).
  4. Tighten
    Tighten the Heated Oxygen Sensor to 41 N·m (30 lb ft).

    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.

  5. Connect the electrical connector.