GM Service Manual Online
For 1990-2009 cars only

Catalytic Converter Replacement L26

Removal Procedure


    Object Number: 911163  Size: SH

    Important: The catalytic converter is serviced by replacing the entire assembly. Always replace the gaskets at the front and rear flanges when servicing the catalytic converter. Never install the original gasket.

  1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .
  2. Disconnect the heated oxygen sensor (HO2S) electrical connector.
  3. Remove the catalytic converter pipe stud nuts (2).
  4. Remove the catalytic converter pipe gasket (1).
  5. Support the exhaust system.

  6. Object Number: 212193  Size: SH
  7. Remove the catalytic converter nuts.
  8. Remove the catalytic converter.
  9. Remove the catalytic converter gasket.
  10. Clean and inspect the exhaust manifold and the exhaust pipe gasket mating surfaces.
  11. Remove the HO2S. Refer to Heated Oxygen Sensor 2 Replacement .

Installation Procedure


    Object Number: 212193  Size: SH
  1. Install the HO2S. Refer to Heated Oxygen Sensor 2 Replacement .
  2. Notice: To prevent internal damage to the flexible coupling of the catalytic converter assembly, the converter must be supported. The vertical movement at the rear of the catalytic converter assembly must not exceed 6 degrees up or down.

  3. Install a new gasket to the exhaust pipe studs.
  4. Install and support the catalytic converter.
  5. Notice: Refer to Fastener Notice in the Preface section.

  6. Install the catalytic converter nuts.
  7. Tighten
    Tighten the nuts to 60 N·m (44 lb ft).


    Object Number: 911163  Size: SH
  8. Install a new catalytic converter pipe gasket (1).
  9. Install the catalytic converter pipe stud nuts (2).
  10. Tighten
    Tighten the nuts to 35 N·m (26 lb ft).

  11. Remove the support from the exhaust system.
  12. Connect the HO2S electrical connector.
  13. Inspect the exhaust system for leaks and underbody contact.
  14. Lower the vehicle.

Catalytic Converter Replacement LD8

Removal Procedure

Caution: In order to avoid being burned, do not service the exhaust system while it is still hot. Service the system when it is cool.

Caution: Always wear protective goggles and gloves when removing exhaust parts as falling rust and sharp edges from worn exhaust components could result in serious personal injury.

  1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .
  2. Support the exhaust system near the resonator with a suitable jack.
  3. Remove the oxygen sensor. It is not necessary to disconnect the electrical connector.

  4. Object Number: 71703  Size: SH
  5. Remove the nuts securing the catalytic converter to the exhaust manifold pipe.

  6. Object Number: 691380  Size: SH
  7. Remove the bolts securing the center exhaust hangers to the rear suspension support brackets.
  8. Remove the catalytic converter from the manifold pipe.
  9. Lower the exhaust system.

  10. Object Number: 1761294  Size: SH
  11. Remove the catalytic converter gasket (1). Do not reuse the gasket.

  12. Object Number: 1761299  Size: SH

    Important: Ensure the cut (1) is made 34 mm (1.3 in) from the weld on the intermediate pipe.

  13. Cut the intermediate pipe 34 mm (1.3 in) from the resonator weld.

Installation Procedure


    Object Number: 1761302  Size: SH
  1. Slide 2 service clamps (1) over the catalytic converter assembly outlet pipe.
  2. Do not tighten at this time.


    Object Number: 1761305  Size: SH

    Important: Ensure the O2 sensor boss is facing the right side of the vehicle.

  3. Slide the catalytic converter assembly (1) outlet pipe over the intermediate pipe (2).

  4. Object Number: 71703  Size: SH

    Notice: When inspecting or replacing exhaust system components, make sure there is adequate clearance from all points on the underbody to prevent overheating of the floor pan and possible damage to the passenger compartment insulation and trim materials.

  5. Place a NEW catalytic converter gasket over the catalytic converter studs.
  6. Notice: Do not over-flex or damage the flex joint when moving the flex joint from the normal mounting position.

  7. Raise the exhaust system into position, aligning the catalytic converter with the exhaust manifold pipe.
  8. Install the nuts securing the catalytic converter to the exhaust manifold pipe.
  9. Do not tighten at this time.

    Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 691380  Size: SH
  10. Install the bolts securing the center exhaust hangers to the rear suspension support brackets.
  11. Tighten
    Tighten the center exhaust hanger bolts to 30 N·m (22 lb ft).

  12. Tighten the catalytic converter nuts.
  13. Tighten
    Tighten the catalytic converter nuts in a crisscross pattern to 25 N·m (18 lb ft).

  14. Remove the jack from under the vehicle.

  15. Object Number: 1761308  Size: SH
  16. Position the service clamps midway on the catalytic converter assembly outlet pipe, as close together as possible.
  17. Rotate the clamps so the fastening ends are pointing in opposite directions.
  18. Tighten
    Tighten the service clamps to 54 N·m (40 lb ft).

  19. Lower the vehicle.
  20. Check the exhaust system for leaks.