GM Service Manual Online
For 1990-2009 cars only

Tools Required

J 39194 Oxygen Sensor Wrench.

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: Use 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 will not operate properly.

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

    Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

  1. Disconnect the negative battery cable.

  2. Object Number: 12348  Size: SH
  3. If the heated oxygen sensor 2 (HO2S 2) is being replaced, raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.

  4. Object Number: 32187  Size: SH
  5. Disconnect the HO2S electrical connector.
  6. Use the J 39194 oxygen sensor wrench in order to carefully back the HO2S out of the exhaust.

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 burns away, but the glass beads remain, making the sensor easier to remove. New or service sensors already have the compound applied to the threads. If a sensor is removed from an engine and is to be reinstalled, the threads must have anti-seize compound applied before reinstallation.


    Object Number: 32187  Size: SH
  1. Coat the threads of the heated oxygen sensor/catalyst monitor with anti-seize compound GM P/N 5613695, or equivalent, if necessary.

  2. Object Number: 12348  Size: SH

    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. Use the J 39194 oxygen sensor wrench in order to install the HO2S.
  4. Tighten
    Tighten the HO2S to 41 N·m (30 lb ft).

  5. Connect the HO2S sensor electrical connector.
  6. Connect the negative battery cable.