Catalytic Converter: Service and Repair

Catalytic Converter Replacement (RPOs LZE/LZ4/LZ8) (3.5L)

Removal Procedure

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. Remove the intake manifold cover. Refer to Intake Manifold Cover Replacement (Service and Repair)
2. Remove the connector position assurance (CPA) retainer (3).
3. Remove the heated oxygen sensor (HO2S) electrical connector clip (1) from the ignition coil bracket.
4. Disconnect the HO2S electrical connector (2).




5. Remove the exhaust manifold heat shield bolts.
6. Remove the exhaust manifold heat shield.
7. Remove the upper catalytic converter to exhaust manifold nut.




8. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle Service and Repair
9. Remove the CPA retainer (1).
10. Disconnect the HO2S electrical connector (3).




11. Remove the HO2S. Refer to Heated Oxygen Sensor 2 Replacement Service and Repair
12. Support the exhaust system.




13. Remove the catalytic converter to muffler nuts.




14. Remove the catalytic converter insulators (1).




15. Remove the catalytic converter lower nut (3).
16. Reposition the muffler assembly rearward until the catalytic converter can be removed.
17. Remove the catalytic converter (3).
18. Remove the catalytic converter gasket (2).
19. Clean and inspect the exhaust manifold and the exhaust pipe gasket mating surfaces.



Installation Procedure





1. Install the catalytic converter gasket (2) onto the catalytic converter.
2. Reposition the muffler assembly rearward until the catalytic converter can be installed.
3. Install the catalytic converter (3).

Notice: Refer to Fastener Notice Fastener Notice

4. Install the catalytic converter lower nut (3).

Tighten the nut to 35 N.m (26 lb ft).





5. Install the catalytic converter insulators (1).




6. Install the catalytic converter to muffler nuts.

Tighten the nuts to 60 N.m (44 lb ft).

7. Remove the support from the exhaust system.




8. Install the HO2S. Refer to Heated Oxygen Sensor 2 Replacement Service and Repair




9. Connect the HO2S electrical connector (3).
10. Install the CPA retainer (1).
11. Lower the vehicle.
12. Install the upper catalytic converter to exhaust manifold nut (1).

Tighten the nut to 35 N.m (26 lb ft).





13. Install the exhaust manifold heat shield.
14. Install the exhaust manifold heat shield bolts.

Tighten the nuts to 10 N.m (89 lb in).





15. Connect the HO2S electrical connector (2).
16. Install the connector position assurance (CPA) retainer (3).
17. Install the HO2S electrical connector clip (1) to the ignition coil bracket.
18. Install the intake manifold cover. Refer to Intake Manifold Cover Replacement (Service and Repair)