GM Service Manual Online
For 1990-2009 cars only

Tools Required

J 39194-B Oxygen Sensor Wrench

Removal Procedure

  1. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  2. Disconnect the pre and post heated oxygen sensor connectors.

  3. Object Number: 231131  Size: SH
  4. Remove the muffler pipe flange bolts.

  5. Object Number: 231136  Size: SH
  6. Remove the exhaust manifold flange nuts.

  7. Object Number: 159595  Size: SH
  8. Remove the catalytic converter support bracket bolts.
  9. Remove the catalytic converters from the muffler pipe flange.

  10. Object Number: 231136  Size: SH
  11. Remove the muffler pipe flange gasket.
  12. Use J 39194-B to remove the heated oxygen sensors.

Installation Procedure

    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.

  1. Use J 39194-B to install the heated oxygen sensors.
  2. Tighten
    Tighten the heated oxygen sensor to 42 N·m (31 lb ft).


    Object Number: 231131  Size: SH
  3. Install the muffler pipe flange gasket.
  4. Install the catalytic converters to the muffler pipe flange.

  5. Object Number: 159595  Size: SH
  6. Install the catalytic converter support bracket bolts.
  7. Tighten
    Tighten the catalytic converter support bracket bolts to 20 N·m (15 lb ft).


    Object Number: 231136  Size: SH
  8. Install the exhaust manifold flange nuts.
  9. Tighten
    Tighten the exhaust manifold flange nuts to 25 N·m (18 lb ft).


    Object Number: 231131  Size: SH
  10. Install the muffler pipe flange nuts.
  11. Tighten
    Tighten the muffler pipe flange nuts to 40 N·m (30 lb ft).

  12. Connect the pre and post heated oxygen sensor connectors.
  13. Inspect all exhaust system clearances. Refer to Exhaust System Clearances .
  14. Start the engine and inspect the exhaust system for leaks.
  15. Lower the vehicle.