GM Service Manual Online
For 1990-2009 cars only

Catalytic Converter Replacement - Left Side LY7

Removal Procedure

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

    Warning: Refer to Protective Goggles and Glove Warning in the Preface section.


    Object Number: 1840273  Size: SH
  1. Remove the exhaust manifold heat shield. Refer to Exhaust Manifold Heat Shield Replacement - Left Side.
  2. Remove the left catalytic converter to exhaust manifold nuts (1).
  3. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle.

  4. Object Number: 1839013  Size: SH
  5. Disconnect the bank 2 sensor 2 heated oxygen sensor (HO2S) electrical connector (3) from the engine wiring harness electrical connector (3).

  6. Object Number: 1840317  Size: SH
  7. Remove the left catalytic converter (3) to right catalytic converter (1) nuts (2).

  8. Object Number: 1840318  Size: SH
  9. Remove the left catalytic converter from the vehicle.
  10. Discard the catalytic converter to exhaust manifold gasket (2).
  11. Discard the left catalytic converter to right catalytic converter gasket (1).

Installation Procedure


    Object Number: 1840318  Size: SH
  1. Install a NEW catalytic converter seal (2) onto the catalytic converter.
  2. Install the catalytic converter to the vehicle.
  3. Install a NEW left catalytic converter to right catalytic converter gasket (1).
  4. Caution: Refer to Fastener Caution in the Preface section.


    Object Number: 1840317  Size: SH
  5. Install the left catalytic converter to right catalytic converter nuts (2) and tighten to 25 N·m (18 lb ft).

  6. Object Number: 1839013  Size: SH
  7. Connect the bank 2 sensor 2 HO2S electrical connector (3) to the engine wiring harness electrical connector (2).

  8. Object Number: 1840273  Size: SH
  9. Install the left catalytic converter to exhaust manifold nuts (1) and tighten to 45 N·m (33 lb ft).
  10. Install the exhaust manifold heat shield. Refer to Exhaust Manifold Heat Shield Replacement - Left Side.
  11. Lower the vehicle and inspect for exhaust leaks.