Catalytic Converter: Service and Repair

Three-way catalytic converter (TWC), replacing

Special tools:
999 5972 FIXTURE 999 5972 Fixture
999 5543 SOCKET NV-22 HO2S 999 5543 Socket NV-22 HO2S

Removing the three-way catalytic converter (TWC)

Note! The illustrations in this service information are used for different model years and/or models. Some variation may occur. However, the essential information in the illustrations is always correct.

Removing the three-way catalytic converter (TWC)





Remove
- heat deflector plate over the manifold
- the air preheating hose
Separate the heated oxygen sensor (HO2S) connectors.




- the splash guard under the engine
- the nuts at the junction of the manifold and the front exhaust pipe
- the nuts where the exhaust pipe divides downstream of the three-way catalytic converter (TWC)
- the left front wheel.
Release the wiring for the heated oxygen sensor (HO2S) from the rear engine mounting and the steering gear.
Remove the screws securing the front SIPS member to the bodywork.
Press the brake pipe out of the holders on the SIPS member.




Press the rear exhaust system backward so that the front section hangs off at the joint downstream of the three-way catalytic converter (TWC).

Hint: Use a mobile jack and universal plate 999 5972 FIXTURE 999 5972 Fixture as a support.

Lower and pull back the three-way catalytic converter (TWC) with the SIPS member.

Note! Ensure that the heated oxygen sensor (HO2S) wiring does not catch when lowering.

Installing the three-way catalytic converter (TWC)

Note! For tightening torques, see: Tightening torque Tightening Torque.

Note! To ensure that there is no exhaust leakage, see: Flanged joint, assembling Service and Repair.

Transferring components

Transfer
- the SIPS member with the exhaust system mountings
- the heated oxygen sensors (HO2S).

Note! The front and rear heated oxygen sensors (HO2S) are not interchangeable.

Tighten the heated oxygen sensors (HO2S) to 45 Nm. Use tool 999 5543 SOCKET NV-22 HO2S 999 5543 Socket NV-22 HO2S.

Installing the three-way catalytic converter (TWC)




Lubricate the studs at the flange on the manifold. Use paste (P/N 116 1408). Avoid skin contact with the paste.
Lift the front exhaust system. Connect the front exhaust system to the rear system. Use a new gasket and new nuts. Do not tighten.
Then connect to the manifold. Use a new gasket and new nuts. Do not tighten.

Note! Ensure that the routing of the wiring for the heated oxygen sensors (HO2S) is the same as before.





Install
- the screws securing the SIPS member to the bodywork
- the brake pipe in the holders on the SIPS member.
Tighten the front and rear sections of the exhaust system. Tighten the front SIPS member. Tighten to 25 Nm.
Secure the wiring for the heated oxygen sensors (H02S) at the rear engine mounting and at the steering gear.
- the splash guard under the engine
- the left-hand front wheel. See Installing wheels Service and Repair.
Connect the heated oxygen sensor (HO2S) connectors.
Reinstall the air preheating hose.

Check
Test drive the engine and note any exhaust leakage.