Catalytic Converter: Service and Repair

Catalytic Converter Replacement (4.81- and 5.31- Engines)

Removal Procedure





1. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
2. Remove the engine shield bolts and shield, if necessary.





3. Remove the oil pan skid plate bolts and plate, if necessary.





4. Unclip the oxygen sensor connection from the floor reinforcement.





5. Remove the clip from around the engine harness and the oxygen sensor pigtail.
6. Disconnect the connector position assurance (CPA) retainers.
7. Disconnect the oxygen sensor electrical connectors.





8. Unclip the oxygen sensors electrical connectors from the following:
- Hose clip
- Transmission crossmember
9. Disconnect the CPA retainers.
10. Disconnect the oxygen sensor electrical connectors (1, 2).





11. Remove the left exhaust manifold pipe nuts.





12. Remove the right exhaust manifold pipe nuts.





13. Remove the exhaust muffler nuts.
14. Remove the catalytic converter.





15. Remove the oxygen sensors if the catalytic converter is to be replaced.

Installation Procedure





Notice: Refer to Fastener Notice in Cautions and Notices.

1. If the catalytic converter was replaced, perform the following:
1.1. Apply anti-seize compound GM P/N 12377953 or equivalent to the threads of the old oxygen sensors.
1.2. Install the oxygen sensors.
- Tighten the oxygen sensors to 42 Nm (31 ft. lbs.).
2. Install the catalytic convertor.





3. Install NEW exhaust manifold pipe seals to the exhaust manifolds.
4. Install the right exhaust manifold pipe nuts until sung.





5. Install the left exhaust manifold pipe nuts until snug.
6. Tighten the right and left exhaust manifold pipe nuts.
- Tighten the nuts to 50 Nm (39 ft. lbs.).





7. Install the exhaust muffler nuts.
- Tighten the nuts to 40 Nm (30 ft. lbs.).





8. Connect the oxygen sensor electrical connectors (1, 2).
9. Connect the CPA retainers.
10. Clip the oxygen sensors electrical connectors to the following:
- Hose clip
- Transmission crossmember





11. Connect the oxygen sensor electrical connectors.
12. Connect the CPA retainers.
13. Install the clip around the engine harness and the oxygen sensor pigtail.





14. Clip the oxygen sensor connection to the floor reinforcement.





15. Install the oil pan skid plate and bolts, if necessary.
- Tighten the bolts to 20 Nm (15 ft. lbs.)





16. Install the engine shield and bolts, if necessary.
- Tighten the bolts to 20 Nm (15 ft. lbs.).
17. Lower the vehicle.