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For 1990-2009 cars only

Catalytic Converter Replacement LX9 - Front

Tools Required

J 39194-B Heated Oxygen Sensor Wrench

Removal Procedure


    Object Number: 1492084  Size: SH
  1. Remove the front catalytic converter nuts (1) at the exhaust manifold.
  2. Remove the muffler assembly. Refer to Muffler Replacement .

  3. Object Number: 1492091  Size: SH
  4. Remove the rear heated oxygen sensor (HO2S) connector position assurance (CPA) retainer (1).
  5. Important: The HO2S uses a permanently attached pigtail and connector. This pigtail should not be removed from the sensor. Damage or removal of the pigtail or connector will affect proper operation of the sensor.

  6. Disconnect the rear HO2S electrical connector  (2).

  7. Object Number: 1492090  Size: SH
  8. Remove the front HO2S CPA retainer (2).
  9. Important: The HO2S uses a permanently attached pigtail and connector. This pigtail should not be removed from the sensor. Damage or removal of the pigtail or connector will affect proper operation of the sensor.

  10. Disconnect the front HO2S electrical connector (1).

  11. Object Number: 1492088  Size: SH
  12. Remove the front and rear HO2Ss (1, 2) using the J 39194-B .

  13. Object Number: 1492085  Size: SH
  14. Remove the rear catalytic converter bolt (4) and nuts (1) at the exhaust manifold.
  15. Remove and discard the gasket (2).
  16. Remove the rear catalytic converter (3).

  17. Object Number: 1492086  Size: SH
  18. Remove the front catalytic converter to rear catalytic converter nuts (3). (Powertrain shown removed for clarity).
  19. Remove the front catalytic converter (1)
  20. Remove and discard the front catalytic converter to manifold gasket.
  21. Inspect the catalytic converter-to-exhaust manifold flange.
  22. Catalytic Converter to Manifold Flange Warpage:

        • Service Limit: 0.7 mm (0.028 in) max.
        • Standard: 0.7 mm (0.028 in) max.

Installation Procedure


    Object Number: 1492085  Size: SH
  1. Install a NEW gasket to the front catalytic converter studs.
  2. Install the front catalytic converter (1)
  3. Install a NEW gasket (2) to the rear catalytic converter studs.
  4. Install the rear catalytic converter (3).
  5. Notice: Refer to Fastener Notice in the Preface section.

  6. Install the rear catalytic converter bolt (4) and nuts (1) at the exhaust manifold.
  7. Tighten
    Tighten the bolt and nuts to 31 N·m (23 lb ft).


    Object Number: 1492086  Size: SH
  8. Install the front catalytic converter to rear catalytic converter nuts (3). (Powertrain shown removed for clarity).
  9. Tighten
    Tighten the nuts to 31 N·m (23 lb ft).


    Object Number: 1492088  Size: SH
  10. Install the front and rear HO2Ss (1, 2) using the J 39194-B .
  11. Tighten
    Tighten the sensor to 42 N·m (31 lb ft).


    Object Number: 1492090  Size: SH
  12. Connect the front HO2S electrical connector (1).
  13. Install the front HO2S CPA retainer (2).

  14. Object Number: 1492091  Size: SH
  15. Disconnect the rear HO2S electrical connector (2).
  16. Install the rear HO2S CPA retainer (1).
  17. Install the muffler assembly. Refer to Muffler Replacement .

  18. Object Number: 1492084  Size: SH
  19. Install the front catalytic converter nuts (1) at the exhaust manifold.
  20. Tighten
    Tighten the nuts to 31 N·m (23 lb ft).

  21. Start the engine, and check for exhaust leaks.

Catalytic Converter Replacement LX9 - Rear

Tools Required

J 39194-B Heated Oxygen Sensor Wrench

Removal Procedure


    Object Number: 1492091  Size: SH
  1. Remove the muffler assembly. Refer to Muffler Replacement .
  2. Remove the connector position assurance (CPA) retainer (1).
  3. Important: The heated oxygen sensor (HO2S) 2 uses a permanently attached pigtail and connector. This pigtail should not be removed from the sensor. Damage or removal of the pigtail or connector will affect proper operation of the sensor.

  4. Disconnect the HO2S electrical connector (2).

  5. Object Number: 1492088  Size: SH
  6. Remove the HO2S (2) using the J 39194-B .

  7. Object Number: 1492086  Size: SH
  8. Remove the front catalytic converter to rear catalytic converter nuts (3). (Powertrain shown removed for clarity).

  9. Object Number: 1492085  Size: SH
  10. Remove the catalytic converter bolt (4) and nuts (1) at the exhaust manifold.
  11. Remove the rear catalytic converter  3).
  12. Remove and discard the gasket (2).
  13. Inspect the catalytic converter-to-exhaust manifold flange.
  14. Catalytic Converter to Manifold Flange Warpage:

        • Service Limit: 0.7 mm (0.028 in) max.
        • Standard: 0.7 mm (0.028 in) max.

Installation Procedure


    Object Number: 1492085  Size: SH
  1. Install a NEW gasket (2) to the catalytic converter studs.
  2. Install the rear catalytic converter (3).
  3. Notice: Refer to Fastener Notice in the Preface section.

  4. Install the catalytic converter bolt (4) and nuts (1) at the exhaust manifold.
  5. Tighten
    Tighten the bolt and nuts to 31 N·m (23 lb ft).


    Object Number: 1492086  Size: SH
  6. Install the front catalytic converter to rear catalytic converter nuts (3). (Powertrain shown removed for clarity).
  7. Tighten
    Tighten the nuts to 31 N·m (23 lb ft).


    Object Number: 1492088  Size: SH
  8. Install the HO2S (2) using the J 39194-B .
  9. Tighten
    Tighten the sensor to 42 N·m (31 lb ft).


    Object Number: 1492091  Size: SH
  10. Connect the HO2S electrical connector (2).
  11. Install the CPA retainer (1).
  12. Install the muffler assembly. Refer to Muffler Replacement .
  13. Start the engine, and check for exhaust leaks.

Catalytic Converter Replacement 3.9L Engine - Front

Tools Required

J 39194-B Heated Oxygen Sensor Wrench

Removal Procedure

  1. Remove the air cleaner assembly. Refer to Air Cleaner Assembly Replacement .

  2. Object Number: 1581869  Size: SH
  3. Remove the connector position assurance (CPA) retainer (5).
  4. Disconnect the heated oxygen sensor (HO2S) electrical connector (4).
  5. Remove the HO2S clip (3) from the oil level indicator tube bracket.

  6. Object Number: 1585276  Size: SH
  7. Remove the exhaust manifold heat shield bolts.
  8. Remove the exhaust manifold heat shield.

  9. Object Number: 1492084  Size: SH
  10. Remove the left (front) catalytic converter nuts (1) at the exhaust manifold.
  11. Remove the muffler assembly. Refer to Muffler Replacement .

  12. Object Number: 1586009  Size: SH
  13. Remove the lower right heated oxygen sensor HO2S connector position assurance (CPA) retainer (1).
  14. Disconnect the rear HO2S electrical connector (2).

  15. Object Number: 1586008  Size: SH
  16. Remove the lower left HO2S CPA retainer (1).
  17. Disconnect the front HO2S electrical connector (2).

  18. Object Number: 1492088  Size: SH

    Notice: The oxygen sensor uses a permanently attached pigtail and connector. Do not remove the pigtail from the oxygen sensor. Damage to or removal of the pigtail connector could affect proper operation of the oxygen sensor.

  19. Remove the lower right and left HO2S (1, 2) using the J 39194-B .

  20. Object Number: 1684169  Size: SH
  21. Remove the left (front) catalytic converter to right (rear) catalytic converter nuts (3).
  22. Remove the right (rear) catalytic converter bolt (5) and nuts (1) at the exhaust manifold.
  23. Remove and discard the gasket (6).
  24. Remove the right (rear) catalytic converter (2).
  25. Remove the left (front) catalytic converter (4).
  26. Remove and discard the left (front) catalytic converter to manifold gasket.
  27. Inspect the catalytic converter-to-exhaust manifold flange.
  28. Catalytic Converter to Manifold Flange Warpage

        • Service Limit: 0.7 mm (0.028 in) max.
        • Standard: 0.7 mm (0.028 in) max.

Installation Procedure


    Object Number: 1684169  Size: SH
  1. Install a NEW gasket to the left (front) catalytic converter studs.
  2. Install the left (front) catalytic converter (4).
  3. Install a NEW gasket (6) to the right (rear) catalytic converter studs.
  4. Install the right (rear) catalytic converter (2).
  5. Notice: Refer to Fastener Notice in the Preface section.

  6. Install the right (rear) catalytic converter bolt (5) and nuts (1) at the exhaust manifold.
  7. Tighten
    Tighten the bolt and nuts to 31 N·m (23 lb ft).

  8. Install the left (front) catalytic converter to right (rear) catalytic converter nuts (3).
  9. Tighten
    Tighten the nuts to 31 N·m (23 lb ft).


    Object Number: 1492088  Size: SH

    Important: A special anti-seize compound is used on the HO2S threads. The compound consists of liquid graphite and glass beads. The graphite tends to burn away but the beads remain, making the sensor easier the remove. New, or service replacement sensors already have the compound applied to the threads. If the sensor is removed from an exhaust component and if for any reason the sensor is to be reinstalled, the threads must be have anti-seize compound applied before the reinstallation.

  10. If reinstalling the old HO2S, coat the threads with anti-seize compound GM P/N 12377953 or equivalent.
  11. Install the lower right and left HO2S (1, 2) using the J 39194-B .
  12. Tighten
    Tighten the sensor to 42 N·m (31 lb ft).


    Object Number: 1586008  Size: SH
  13. Connect the lower left HO2S electrical connector (1).
  14. Install the lower left HO2S CPA retainer (2).

  15. Object Number: 1586009  Size: SH
  16. Connect the lower right HO2S electrical connector (2).
  17. Install the lower right HO2S CPA retainer (1).
  18. Install the muffler assembly. Refer to Muffler Replacement .

  19. Object Number: 1492084  Size: SH
  20. Install the left (front) catalytic converter nuts (1) at the exhaust manifold.
  21. Tighten
    Tighten the nuts to 31 N·m (23 lb ft).


    Object Number: 1585276  Size: SH
  22. Install the exhaust manifold heat shield.
  23. Install the exhaust manifold heat shield bolts.
  24. Tighten
    Tighten the bolts to 10 N·m (89 lb in).


    Object Number: 1581869  Size: SH
  25. Connect the HO2S electrical connector (4).
  26. Install the CPA retainer (5).
  27. Install the HO2S clip (3) to the oil level indicator tube bracket.
  28. Install the air cleaner assembly. Refer to Air Cleaner Assembly Replacement .
  29. Perform the engine mount position adjustment procedure. Refer to Engine Mount Position Adjustment .
  30. Start the engine, and check for exhaust leaks.

Catalytic Converter Replacement 3.9L Engine - Rear

Tools Required

J 39194-B Heated Oxygen Sensor Wrench

Removal Procedure


    Object Number: 1586008  Size: SH
  1. Remove the muffler assembly. Refer to Muffler Replacement .
  2. Remove the rear stabilizer shaft. Refer to Stabilizer Shaft Replacement .
  3. Remove the connector position assurance (CPA) retainer (1).
  4. Disconnect the lower right heated oxygen sensor (HO2S) electrical connector (2).

  5. Object Number: 1492088  Size: SH

    Notice: The oxygen sensor uses a permanently attached pigtail and connector. Do not remove the pigtail from the oxygen sensor. Damage to or removal of the pigtail connector could affect proper operation of the oxygen sensor.

  6. Remove the lower right HO2S (2) using the J 39194-B .

  7. Object Number: 1684169  Size: SH
  8. Remove the left (front) catalytic converter to right (rear) catalytic converter nuts (3).
  9. Remove the right (rear) catalytic converter bolt (5) and nuts (1) at the exhaust manifold.
  10. Remove the right catalytic converter (2).
  11. Remove and discard the gasket (6).
  12. Inspect the catalytic converter-to-exhaust manifold flange.
  13. Catalytic Converter to Manifold Flange Warpage:

        • Service Limit: 0.7 mm (0.028 in) max.
        • Standard: 0.7 mm (0.028 in) max.

Installation Procedure


    Object Number: 1684169  Size: SH
  1. Install a NEW gasket to the catalytic converter.
  2. Install the right (rear) catalytic converter (2).
  3. Notice: Refer to Fastener Notice in the Preface section.

  4. Install the right (rear) catalytic converter bolt (4) and nuts (1) at the exhaust manifold.
  5. Tighten
    Tighten the nuts to 31 N·m (23 lb ft).

  6. Install the left (front) catalytic converter to right (rear) catalytic converter nuts (3).
  7. Tighten
    Tighten the nuts to 31 N·m (23 lb ft).


    Object Number: 1492088  Size: SH

    Important: A special anti-seize compound is used on the HO2S threads. The compound consists of liquid graphite and glass beads. The graphite tends to burn away but the beads remain, making the sensor easier the remove. New, or service replacement sensors already have the compound applied to the threads. If the sensor is removed from an exhaust component and if for any reason the sensor is to be reinstalled, the threads must be have anti-seize compound applied before the reinstallation.

  8. If reinstalling the old HO2S, coat the threads with anti-seize compound GM P/N 12377953 or equivalent.
  9. Install the HO2S (2) using the J 39194-B .
  10. Tighten
    Tighten the sensor to 42 N·m (31 lb ft).


    Object Number: 1586008  Size: SH
  11. Connect the lower right HO2S electrical connector (2).
  12. Install the CPA retainer (1).
  13. Ensure that the HO2S connector clip (3) is attached to the stud on the engine.
  14. Install the rear stabilizer shaft. Refer to Stabilizer Shaft Replacement .
  15. Install the muffler assembly. Refer to Muffler Replacement .
  16. Perform the engine mount position adjustment procedure. Refer to Engine Mount Position Adjustment .
  17. Start the engine, and check for exhaust leaks.