GM Service Manual Online
For 1990-2009 cars only

Catalytic Converter Replacement Gasoline Engines

Removal Procedure

    Warning: Refer to Exhaust Service Warning in the Preface section.

    Warning: Refer to Battery Disconnect Warning in the Preface section.

    Caution: Refer to Flex Decoupler Caution in the Preface section.

    Caution: Refer to Catalytic Converter Movement Caution in the Preface section.


    Object Number: 1252135  Size: SH
  1. Disconnect the negative battery cable.
  2. Remove the spark plug cover.

  3. Object Number: 1252124  Size: SH
  4. Remove the exhaust manifold heat shield bolts and the heat shield.

  5. Object Number: 1252162  Size: SH
  6. Remove the catalytic converter upper flange nuts.

  7. Object Number: 1252123  Size: SH
  8. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle
  9. Remove the splash guard. Refer to Engine Shield Replacement
  10. Remove the catalytic converter lower flange nuts.

  11. Object Number: 1252142  Size: SH
  12. Remove the front exhaust pipe mounting bracket bolts and bracket.
  13. Remove the catalytic converter.

Installation Procedure

    Caution: Refer to Fastener Caution in the Preface section.


    Object Number: 1252142  Size: SH
  1. Fit the catalytic converter onto the connecting pipe, raise the front exhaust pipe, and install the front exhaust pipe mounting bracket nuts and bracket and tighten to 30 N·m (22 lb ft).

  2. Object Number: 1252123  Size: SH
  3. Install the catalytic converter lower flange nuts and tighten to 40 N·m (30 lb ft).

  4. Object Number: 1252162  Size: SH
  5. Install the splash guard. Refer to Engine Shield Replacement
  6. Lower the vehicle.
  7. Install the catalytic converter upper flange bolts and tighten to 40 N·m (30 lb ft).

  8. Object Number: 1252124  Size: SH
  9. Install the exhaust manifold heat shield and heat shield bolts and tighten to 3 N·m (27 lb ft)

  10. Object Number: 1252135  Size: SH
  11. Install the exhaust cover mounting bolts and the engine cover.
  12. Connect the negative battery cable.

Catalytic Converter Replacement Diesel Engine

Removal Procedure

    Warning: Refer to Battery Disconnect Warning in the Preface section.


    Object Number: 1820482  Size: SH

    Warning: 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: 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.

  1. Disconnect the negative battery cable.
  2. Remove the exhaust manifold heat shield.

  3. Object Number: 1820483  Size: SH
  4. Remove the exhaust front pipe.
  5. Remove the pre-catalyst clamp.
  6. Remove the pre-catalyst bracket bolt from the engine block.
  7. Remove the pre-catalyst with the seal ring.

Installation Procedure


    Object Number: 1820483  Size: SH
  1. Install the pre-catalyst with the seal ring. If damaged, replace the new seal ring.
  2. Caution: Refer to Fastener Caution in the Preface section.

  3. Install the pre-catalyst clamp and the bracket bolt and tighten to 40 N·m (29.5 lb ft).
  4. Install the exhaust front pipe. Refer to Front Pipe Replacement

  5. Object Number: 1820482  Size: SH
  6. Install the exhaust manifold heat shield and tighten to 20 N·m (14.8 lb ft).
  7. Connect the negative battery cable.