Warning: Refer to Protective Goggles and Glove Warning in the Preface section.

Warning: Refer to Exhaust Service Warning in the Preface section.

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



4. If replacing the three way catalytic converter remove the heated oxygen (HO2S) sensors (1 - 5) otherwise disconnect the heated oxygen (HO2S) sensors harness connectors.

•	For the L9H, LY2, or LY5 engines. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 , Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 , Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 and Heated Oxygen Sensor Replacement - Bank 2 Sensor 2.

•	For the LFA engines. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1, Heated Oxygen Sensor Replacement - Bank 1 Sensor 2, Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 and Heated Oxygen Sensor Replacement - Bank 2 Sensor 2




5. Remove the catalytic converter pipe to the exhaust manifold nuts (1).



6. Loosen the band clamp bolt (1).
7. Remove the catalytic converter pipe from the vehicle.
8. Remove the exhaust seals (2 and 3) and discard.

1. Install NEW exhaust manifold seals (2 and 3).
2. Install the catalytic converter pipe to the exhaust manifolds.

Caution: Refer to Fastener Caution in the Preface section.

3. Install the catalytic converter pipe to exhaust manifold nuts (1) and tighten to 50 N·m (37 lb ft).



4. Position the three way converter to the muffler assembly and tighten the clamp bolt (1) to 44 N·m(32 lb ft).
5. Install the transmission crossmember. Refer to Transmission Support Crossmember Replacement.

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.




6. If replacing the three way catalytic converter Install the heated oxygen (HO2S) sensors (1 - 5) otherwise Connect the heated oxygen (HO2S) sensors harness connectors.

•	For the L9H, LY2, or LY5 engines. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 , Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 , Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 and Heated Oxygen Sensor Replacement - Bank 2 Sensor 2.

•	For the LFA engines. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1, Heated Oxygen Sensor Replacement - Bank 1 Sensor 2, Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 and Heated Oxygen Sensor Replacement - Bank 2 Sensor 2

7. Install the oil pan skid plate if equipped. Refer to Oil Pan Skid Plate Replacement.
8. Lower the vehicle.
9. Inspect for exhaust leaks.