Procedures

Replacing The Three-way Catalytic Converter (TWC)

Special Tools: 999 5543, 999 5972.

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 in the illustrations is always correct.

Removing The Three-way Catalytic Converter (TWC)







- Applies to B52x4T: Remove the left front wheel.
- Disconnect the heated oxygen sensor (HO2S) connectors.
- Release the heated oxygen sensor (HO2S) wiring from its mountings.
- Applies only to B52x4T: Remove the lower rear screw for the heat deflector plate above the turbocharger (TC).
- Remove the nuts for the front exhaust system connection to the turbocharger/manifold.
- Remove the SIPS member.
- Remove the clamp where the exhaust system divides downstream of the three-way catalytic converter (TWC).
- Lift off the exhaust pipe from the turbocharger (TC)/manifold and the rear system.
- Lower/draw down the exhaust system.

HINT: Use a mobile jack with universal plate 999 5972 as support.

Transferring Components







- Transfer the heated oxygen sensors (HO2S). Lubricate the threads using paste 1161408.

NOTE: The front and rear heated oxygen sensors (HO2S) are not interchangeable.

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

Installing The Three-way Catalytic Converter (TWC)

NOTE: Ensure that there is no exhaust leakage.

- Lubricate all studs on the turbocharger (TC) using paste, P/N: 11 61 408.
- Lift up the exhaust system and connect it to the rear system.
- Then connect to the turbocharger (TC)/manifold.

HINT: Use a mobile jack with universal plate 999 5972 as support.







- Install new nuts at the turbocharger/manifold connection. Tighten to 25 Nm.

NOTE:
- Ensure that the flange on the exhaust pipe is flush against the turbocharger (TC).
- Applies only to B52x4T:
- A new screw in the rear mounting for the heat deflector plate.
- Secure the heated oxygen sensor (HO2S) wiring at the mounting points. Connect the connectors.

- Install the clamp at the divide downstream of the three-way catalytic converter (TWC).
- Use a new clamp and a new screw.
- Tighten to 25 Nm.

- Install the SIPS member. Tighten to 25 Nm.
- Install the left front wheel.

Check
- Test drive the engine. Check for any leakage.
- Wipe the engine compartment clean.
- Ensure that the steering wheel and gear selector lever are clean.