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 the 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 the engine temperature is below 48°C (120°F). Excessive force may damage the threads in the exhaust manifold or the exhaust pipe.


    Object Number: 12348  Size: SH
  1. If the HO2S 2 is being replaced, raise the vehicle.

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

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: 17134  Size: SH
  1. Coat the threads of the heated oxygen sensor/catalyst monitor with anti-seize compound P/N 5613695, or equivalent, if necessary.

  2. Object Number: 12348  Size: SH
  3. Install the Heated Oxygen Sensor.
  4. Tighten
    Tighten the Heated Oxygen Sensor to 41 N·m (30 lb. ft.).

  5. Connect the electrical connector.