Catalytic Converter: Service and Repair

Front Exhaust Pipe with Catalytic Converter, and Particle Filter Assembly Overview

• The components illustrated correspond to cylinder bank 1. They are a mirror image of the components for cylinder bank 2.





1 Turbocharger

• Turbocharger assembly overview, refer to --> [ Turbocharger Assembly Overview ] Turbocharger Assembly Overview.

2 Gasket

• Replace.

3 25 Nm

4 Heated oxygen sensor, 50 Nm

• Can only be replaced with the engine removed, refer to --> [ Engine, Removing ] Engine Removing.

• Grease threads only with hot bolt paste (G 052 112 A3) (anti-seize compound). Hot bolt paste (G 052 112 A3) must not get into slots on sensor body.

• To remove, use open end wrench for oxygen sensor (3337)

Cylinder bank 1:

• Oxygen sensor (G39)

Cylinder bank 2:

• Heated Oxygen Sensor (HO2S) 2 (G108)

5 Pre-particle filter temperature sensor, 45 Nm

Cylinder bank 1:

• Bank 1 Exhaust Gas Temperature (EGT) sensor 2 (G448)

Cylinder bank 2:

• Particle filter intake temperature sensor 2 (G498)

6 Pressure line

• Ensure seated tightly

Cylinder bank 1:

• To exhaust pressure sensor 1 (G450) location, refer to --> [ Pressure Sensor Locations ]

Cylinder bank 2:

• To exhaust pressure sensor 2 (G451) location, refer to --> [ Pressure Sensor Locations ]

7 Post-particle filter temperature sensor, 45 Nm

• Only for vehicles with engine code BWF

Cylinder bank 1:

• Bank 1 EGT sensor 3 (G496).

Cylinder bank 2:

• Bank 2 EGT sensor 3 (G497).

8 To rear muffler

• --> [ (Item 9) Rear muffler ] Service and Repair.

9 Transmission crossmember

10 Suspended mount

11 Particle filter

• After replacing, the adaptation of the soot load measurement must be set to "0".

12 Front exhaust pipe with catalytic converter

• Can only be replaced when engine is removed. Refer to --> [ Engine, Removing ] Engine Removing.

• For engine code BWF with metering pump connecting pieces at catalytic converter. Refer to --> [ Post Injection Metering Pump ] Service and Repair.

13 Bracket

Pressure Sensor Locations





1 Exhaust pressure sensor 1 (G450)
2 Exhaust pressure sensor 2 (G451)
3 Pressure line, see note below

• The pressure lines from the particle filter to the pressure sensors G450 and G451 are tested for leaks and for this reason can only be replaced as a unit per cylinder. The pressure sensors are installed above the transmission with a bracket and can only be removed and installed with powertrain removed. Refer to --> [ Engine, Removing ] Engine Removing.