Catalytic Converter Replacement 1500

1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle.
2. Remove the oil pan skid plate bolts and skid plate, if equipped.
3. Remove the transmission crossmember. Refer to Transmission Support Crossmember Replacement.



4. Remove the right front connector position assurance (CPA) retainer (2).
5. Disconnect the right front heated oxygen sensor (HO2S) electrical connector from the engine wiring harness electrical connector (1).
6. Remove the right rear CPA retainer (4).
7. Disconnect the engine wiring harness electrical connector (3) from the right rear HO2S electrical connector.
8. Remove the right rear HO2S electrical connector clip from the engine harness clip (5).



9. Remove the left rear CPA retainer (1).
10. Disconnect the left rear HO2S electrical connector from the engine wiring harness electrical connector (3).



11. For vehicles equipped with a 4L60-E/4L70-E automatic transmission perform the following steps, for vehicles equipped with a 6L80-E automatic transmission proceed to step 15.
12. Remove the left front CPA retainer.
13. Disconnect the engine wiring harness electrical connector (2) from the left front HO2S.
14. Remove the left front HO2S electrical connector clip (1) from the fuel line clip.



15. Remove the left front CPA retainer (2).
16. Remove the engine wiring harness electrical connector clip (1) from the fuel line clip.
17. Disconnect the engine wiring harness electrical connector (3) from the left front HO2S.



18. If the vehicle is equipped with regular productions options (RPOs) LC9/LMG/LY5/L76/LY2, remove the catalytic converter to muffler nuts.



19. If the vehicle is equipped with RPO L92, remove the muffler to catalytic converter nuts.
20. Remove the HO2S. Refer to Heated Oxygen Sensor Replacement - Bank 2 Sensor 1.



21. Remove the catalytic converter to exhaust manifold nuts (1).
22. Separate the catalytic converter assembly from the exhaust manifolds.
23. Remove the catalytic converter assembly from the exhaust muffler.
24. If replacing the catalytic converter assembly, perform the following steps, otherwise proceed to step 4 in the installation procedure.
25. Remove the exhaust seals (2 and 3).



26. Remove the HO2S's (1-5) from the catalytic converter assembly.

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 glass beads remain, making the sensor easier to remove. New, or service replacement sensors already have the compound applied to the threads. If the sensor is removed from as exhaust component and if for any reason the sensor is to be reinstalled, the threads must have anti-seize compound applied before the reinstallation.

1. If replacing the catalytic converter assembly, perform the following steps, otherwise proceed to step 4.
2. If reinstalling the old sensors, coat the threads with anti-seize compound GM P/N 12377953, or equivalent.

Notice: Refer to Fastener Notice in the Preface section.

Notice: Replacement components must be the correct part number for the application. Components requiring the use of the thread locking compound, lubricants, corrosion inhibitors, or sealants are identified in the service procedure. Some replacement components may come with these coatings already applied. Do not use these coatings on components unless specified. These coatings can affect the final torque, which may affect the operation of the component. Use the correct torque specification when installing components in order to avoid damage.

3. Install the HO2S's (1-5) to the catalytic converter assembly.

Tighten
Tighten the sensors to 42 N·m (31 lb ft).




4. Install the NEW exhaust seals (2 and 3) as required.
5. Install the catalytic converter assembly to the muffler.
6. Install the catalytic converter assembly to the exhaust manifolds.
7. Install the catalytic converter to exhaust manifold nuts (1).

Tighten
Tighten the nuts to 50 N·m (37 lb ft).

8. Install the HO2S. Refer to Heated Oxygen Sensor Replacement - Bank 2 Sensor 1.



9. If the vehicle is equipped with RPO L92, install the muffler to catalytic converter nuts.

Tighten
Tighten the nuts to 45 N·m (33 lb ft).




10. If the vehicle is equipped with RPOs LC9/LMG/LY5/L76/LY2, install the catalytic converter to muffler nuts.

Tighten
Tighten the nuts to 45 N·m (33 lb ft).




11. For vehicles equipped with a 4L60-E/4L70-E automatic transmission perform the following steps, for vehicles equipped with a 6L80-E automatic transmission proceed to step 13.
12. Install the HO2S electrical connector clip (1) to the fuel line clip.
13. Connect the engine wiring harness electrical connector (2) to the HO2S.
14. Install the CPA retainer.



15. Connect the engine wiring harness electrical connector (3) to the HO2S.
16. Install the engine wiring harness electrical connector clip (1) to the fuel line clip.
17. Install the CPA retainer (2).



18. Connect the left rear HO2S electrical connector to the engine wiring harness electrical connector (3).
19. Install the left rear CPA retainer (1).



20. Install the right rear HO2S electrical connector clip to the engine harness clip (5).
21. Connect the engine wiring harness electrical connector (3) to the right rear HO2S electrical connector.
22. Install the right rear CPA retainer (4).
23. Connect the right front HO2S electrical connector to the engine wiring harness electrical connector (1).
24. Install the right front CPA retainer (2).



25. Install the transmission crossmember. Refer to Transmission Support Crossmember Replacement.
26. Position the oil pan skid plate and install the oil pan skid plate bolts, if equipped.

Tighten
Tighten the bolts to 28 N·m (21 lb ft).

27. Lower the vehicle.