Catalytic Converter: Service and Repair

Replacing the three-way catalytic converter (TWC)

Special tools:
999 5972 FIXTURE 999 5972 Fixture
999 5543 SOCKET NV-22 HO2S 999 5543 Socket NV-22 HO2S
999 5682 Tensioner band 999 5682 Tensioner Band

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

Removing the three-way catalytic converter (TWC)

Removing the three-way catalytic converter (TWC)





Remove
- the splash guard under the engine.
- the left front wheel.





Separate the heated oxygen sensor (HO2S) connectors.
Release heated oxygen sensor (HO2S) wiring from its mountings.

Remove
- the lower rear screw for the heat deflector plate over the turbocharger (TC).
- the nuts for the front exhaust pipe connection to the turbocharger (TC).

Note! The metal hose for the front exhaust pipe is easy to damage if it is twisted. Handle the exhaust hose with care to avoid leakage later.

- the rear SIPS member (does not apply to AWD).

Note! Reinstall the screws to hold the heat deflector plate in position.

- the nuts where the exhaust pipe divides downstream of the three-way catalytic converter (TWC).




Disconnect brake pipes form the holders at the front SIPS member.
Hold up the exhaust pipe at the front. Use retaining strap 999 5682 Tensioner band 999 5682 Tensioner Band. Secure in the jack mounting. (Applies to AWD)
Remove the screws for the front SIPS member.
Lift off the exhaust pipe from the turbocharger (TC) and the rear system.

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

Lower and draw back the exhaust system with the SIPS member.

Note! The heated oxygen sensor (HO2S) wiring routing over the brake pipe.

Installing the three-way catalytic converter (TWC)

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 45Nm. Use tool 999 5543 SOCKET NV-22 HO2S 999 5543 Socket NV-22 HO2S.

Installing the three-way catalytic converter (TWC)




Lubricate the studs on the turbocharger (TC). Use paste, P/N: 1161408. Avoid skin contact with the paste.
Lift up the exhaust system and connect it to the rear system with a new gasket and new nuts. Do not tighten.
Then connect to the turbocharger (TC).

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

Note! The heated oxygen sensor (HO2S) wiring routing over the brake pipe.





Install
- new nuts at the connection to the turbocharger (TC).
- the front SIPS member. Do not tighten yet.
- the brake pipe in holders on the SIPS member.
Tighten the exhaust pipe at the turbocharger (TC) to 25 Nm.

Note! Ensure that the flange on the exhaust pipe is flush against the turbocharger (TC).

- a new screw for the rear mounting for the heat deflector plate.
- the heated oxygen sensor (HO2S) wiring at the mounting points.

Remove the retaining strap at the front edge of the exhaust pipe (applies to AWD).




Press connector halves together.
Tighten the exhaust pipe where it separates downstream of the three-way catalytic converter (TWC) to 25 Nm.
Install rear SIPS member. Tighten to 25 Nm (does not apply to AWD).
Tighten the front SIPS member to 25 Nm.
Install the splashguard under the engine.
Install the left front wheel according to Installing wheels Service and Repair.

Check
Test drive the engine and any exhaust leakage.