GM Service Manual Online
For 1990-2009 cars only

Removal Procedure

  1. Raise the vehicle. Support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  2. Disconnect the electrical connector from the heated oxygen sensor (HO2S 2).

  3. Object Number: 166024  Size: MH
  4. Remove the two bolts and the two springs securing the front pipe to the Three-Way Catalytic Converter (TWC) (3).
  5. Remove the two bolts and the two nuts securing the Three-Way Catalytic Converter (TWC) to the muffler/tail pipe assembly .

  6. Remove one bolt and hanger (2) from the front of the TWC.
  7. Remove one bolt and hanger (2) from the rear of the TWC. Remove the TWC from the vehicle.
  8. Clean the gasket and seal mating surfaces.

Installation Procedure


    Object Number: 166024  Size: MH
  1. Connect the Three-Way Catalytic Converter (TWC) (3) to the vehicle. Secure the front and rear of the TWC with two bolts and two hangers (2).
  2. Install the two bolts and the two nuts securing the Three-Way Catalytic Converter (TWC) to the muffler/tail pipe assembly. Finger tighten the nuts.
  3. Install the two bolts and the two springs securing the front pipe to the Three-Way Catalytic Converter (TWC). Finger tighten the two bolts.

    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.

  4. Align all system components properly in order to prevent any noise or vibrations before tightening the fasteners.
  5. Tighten

        • Tighten the front pipe-to-TWC bolts to 50 N·m (37 lb ft).
        • Tighten the TWC-to-muffler/tail pipe assembly bolts and nuts to 50 N·m (37 lb ft).
  6. Connect the electrical connector to the heated oxygen sensor (HO2S 2).
  7. Lower the vehicle.