GM Service Manual Online
For 1990-2009 cars only

Special Tools

J 39194-C Oxygen Sensor Wrench

Removal Procedure

Caution: 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.

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

Note: 

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

  1. Hoist and raise the vehicle. Refer to Lifting and Jacking the Vehicle.
  2. Remove the connector position assurance (CPA) tab from the HO2S electrical connection.
  3. Disconnect the engine wiring harness electrical connector from the HO2S electrical connector.
  4. Remove the HO2S electrical connector from the thermostat housing.

  5. Object Number: 1631780  Size: SH
  6. Remove the HO2S using wrench J 39194-C .

Installation Procedure

Note: A special anti-seize compound is used on the heated oxygen sensor threads. The compound consists of a liquid graphite and glass beads. The graphite will burn away, but the glass beads will remain, making the heated oxygen sensor easier to remove. New or service replacement heated oxygen sensors will have the compound applied to the threads. If a heated oxygen sensor is removed and is to be reinstalled without replacement then the threads must have an appropriate anti-seize compound applied prior to installation.


    Object Number: 1631780  Size: SH
  1. If necessary, coat the threads of the HO2S with anti-seize compound Saturn P/N 21485279 or equivalent.
  2. Caution: Refer to Fastener Caution in the Preface section.

  3. Install the HO2S using wrench J 39194-C .
  4. Tighten
    Tighten the sensor to 42 N·m (31 lb ft).

  5. Install the HO2S electrical connector to the thermostat housing.
  6. Connect the engine wiring harness electrical connector to the HO2S electrical connector.
  7. Install the CPA tab to the HO2S electrical connection.