Catalytic Converter Replacement - Right Side LZ4

Tools Required

J 39194-B Heated Oxygen Sensor Wrench

1. Remove the muffler assembly. Refer to Muffler Replacement .
2. Remove the connector position assurance (CPA) retainer (1).

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.

3. Disconnect the HO2S electrical connector (2).



4. Remove the HO2S (2) using the J 39194-B .



5. Remove the left catalytic converter to right catalytic converter nuts (3). (Powertrain shown removed for clarity).



6. Remove the catalytic converter bolt (4) and nuts (1) at the exhaust manifold allowing the catalytic converter (3) to rest on the cradle.
7. Reposition the frame until the catalytic converter can be removed.
8. Remove and discard the gasket (2).

1. Install a NEW gasket (2) to the catalytic converter studs.
2. Install the right catalytic converter (3).

Notice: Refer to Fastener Notice in the Preface section.

3. Install the catalytic converter bolt (4) and nuts (1) at the exhaust manifold.

Tighten
Tighten the bolt and nuts to 31 N·m (23 lb ft).




4. Install the left catalytic converter to right catalytic converter nuts (3). (Powertrain shown removed for clarity).

Tighten
Tighten the nuts to 31 N·m (23 lb ft).




5. Install the HO2S (2) using the J 39194-B .

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




6. Connect the HO2S electrical connector (2).
7. Install the CPA retainer (1).
8. Install the muffler assembly. Refer to Muffler Replacement .
9. Start the engine, and check for exhaust leaks.

Catalytic Converter Replacement - Right Side LZ9 w/RPO MT2

Tools Required

J 39194-B Heated Oxygen Sensor Wrench

1. Remove the connector position assurance (CPA) retainer (5).
2. Disconnect the engine harness electrical connector (4) from the heated oxygen sensor (HO2S).
3. Remove the HO2S clip (3) from the oil level indicator tube bracket.



4. Remove the exhaust manifold heat shield bolts.
5. Remove the exhaust manifold heat shield.



6. Remove the right (rear) catalytic converter nuts (1).



7. Remove the muffler assembly. Refer to Muffler Replacement .
8. Remove the rear stabilizer shaft. Refer to Stabilizer Shaft Replacement .
9. Remove the connector position assurance (CPA) retainer (1).
10. Disconnect the HO2S electrical connector (2).




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.

11. Remove the HO2S (2) using the J 39194-B .



12. Remove the left (front) catalytic converter to right (rear) catalytic converter nuts (2).
13. Remove the right (rear) catalytic converter (1).
14. Remove and discard the gasket.
15. Inspect the catalytic converter-to-exhaust manifold flange.

Catalytic Converter to Manifold Flange Warpage:

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

•	Standard: 0.7 mm (0.028 in) max.

1. Install a NEW gasket to the catalytic converter studs.
2. Install the right (rear) catalytic converter (1).

Notice: Refer to Fastener Notice in the Preface section.

3. Install the left (front) catalytic converter to right (rear) catalytic converter nuts (2).

Tighten
Tighten the nuts to 31 N·m (23 lb ft).





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.

4. If reinstalling the old HO2S, coat the threads with anti-seize compound GM P/N 12377953 or equivalent.
5. Install the HO2S (2) using the J 39194-B .

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

6. Lower the vehicle to the ground, start the engine, and check for exhaust leaks.



7. Connect the HO2S electrical connector (2).
8. Install the CPA retainer (1).
9. Install the muffler assembly. Refer to Muffler Replacement .
10. Install the rear stabilizer shaft. Refer to Stabilizer Shaft Replacement .



11. Install the right (rear) catalytic converter nuts (1).

Tighten
Tighten the nuts to 31 N·m (23 lb ft).




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

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




14. Connect the engine harness electrical connector (4) to the HO2S.
15. Install the CPA retainer (5).
16. Install the HO2S clip (3) to the oil level indicator tube bracket.
17. Perform the engine mount position adjustment procedure. Refer to Engine Mount Position Adjustment .
18. Start the engine, and check for exhaust leaks.

Catalytic Converter Replacement - Right Side LZ9 w/RPO M15

Tools Required

J 39194-B Heated Oxygen Sensor Wrench

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).




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.

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



6. Remove the left (front) catalytic converter to right (rear) catalytic converter nuts (3).
7. Remove the right (rear) catalytic converter bolt (5) and nuts (1) at the exhaust manifold.
8. Remove the right catalytic converter (2).
9. Remove and discard the gasket (6).
10. Inspect the catalytic converter-to-exhaust manifold flange.

Catalytic Converter to Manifold Flange Warpage:

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

•	Standard: 0.7 mm (0.028 in) max.

1. Install a NEW gasket to the catalytic converter.
2. Install the right (rear) catalytic converter (2).

Notice: Refer to Fastener Notice in the Preface section.

3. Install the right (rear) catalytic converter bolt (4) and nuts (1) at the exhaust manifold.

Tighten
Tighten the nuts to 31 N·m (23 lb ft).

4. Install the left (front) catalytic converter to right (rear) catalytic converter nuts (3).

Tighten
Tighten the nuts to 31 N·m (23 lb ft).





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.

5. If reinstalling the old HO2S, coat the threads with anti-seize compound GM P/N 12377953 or equivalent.
6. Install the HO2S (2) using the J 39194-B .

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




7. Connect the lower right HO2S electrical connector (2).
8. Install the CPA retainer (1).
9. Ensure that the HO2S connector clip (3) is attached to the stud on the engine.
10. Install the rear stabilizer shaft. Refer to Stabilizer Shaft Replacement .
11. Install the muffler assembly. Refer to Muffler Replacement .
12. Perform the engine mount position adjustment procedure. Refer to Engine Mount Position Adjustment .
13. Start the engine, and check for exhaust leaks.