Remove/install SCR catalytic converter

AR14.40-P-2006CDA

Remove/install SCR catalytic converter

07.04.2016

Engine

651 in model 172

with code U77 (Diesel Emission control BLUETEC (SCR))

1

SCR catalytic converter

6

NOx sensor

2

Clamp

7

Differential pressure sensor pressure line

3

Exhaust tailpipe

8

AdBlue® metering valve

4

Separating point

9

Rubber mount

5

NOx sensor

10

Bracket

 Danger !

Risk of injury. Skin or eye injuries may result when handling hot or glowing objects.

Wear protective gloves, protective clothing and safety glasses, if necessary.

AS00.00-Z-0002-01A

 Danger !

Risk of injury caused by scraping or cutting body parts on sharp vehicle parts

Always wear protective gloves when working on or near sharp and non-deburred vehicle parts.
Deburr repair panels.

AS00.00-Z-0017-01A



Notes on self-locking nuts and bolts

AH00.00-N-0001-01A



Notes on avoiding damage through contamination and foreign objects

AH00.00-P-5000-01A

 

Remove/install

1

Remove lower engine compartment paneling at rear

AR61.20-P-1105W

2

Detach NOx sensors (5, 6) at SCR catalytic converter (1)

AR14.40-P-2038CDA

3

Unscrew union nut for temperature sensor upstream of SCR catalytic converter (1) and remove temperature sensor

AR14.40-P-2011CDA

4

Detach AdBlue® metering valve (8) at SCR catalytic converter (1)

AR14.40-P-2000CDA

5

Detach differential pressure sensor pressure line (7) downstream of diesel particulate filter

 Union nut/retaining screw, pressure line to diesel particulate filter

*BA14.40-P-1001-01E

6

Detach clamp (2)

 Installation: Ensure that the clamp is correctly seated.

 Bolt, clamp to center of exhaust line/diesel particulate filter

*BA49.10-P-1010-01AI

7

Disconnect SCR catalytic converter (1) at connecting point (4) from exhaust tailpipe (3)

8

Remove screw/bolts from bracket (10) on transmission

 Bolt, diesel particulate filter bracket to transmission

*BA49.10-P-1009-01AI

9

Unscrew rubber suspension (9) from body and remove SCR catalytic converter (1)

 Helper required.

 Bolt, exhaust rubber mount bracket to underfloor/rear axle carrier

*BA49.10-P-1012-01AI

10

Detach rubber suspension (9) at SCR catalytic converter (1)

When replacing the SCR catalytic converter (1).



Clean

11

Remove combustion and corrosion residue at separating points

12

Install in the reverse order

13

Connect diagnostic system, read out fault memory and delete if necessary



AD00.00-P-2000-04A

 Danger !

Risk of accident from vehicle starting off by itself when engine running. Risk of injury (bruises and burns) resulting from working on the engine while it is being started or when it is running.

Secure vehicle to prevent it from starting off by itself. Wear closed and snug-fitting work clothes. Do not touch hot or rotating parts.

AS00.00-Z-0005-01A

14

Carry out an engine test run and check exhaust system for leaktightness

 Diesel particulate filter

Number

Designation

Model 117, 156, 172, 176, 204, 205, 207, 212, 218, 222, 246, 253 with engine 651

BA14.40-P-1001-01E

Union nut/retaining screw, pressure line to diesel particulate filter

Nm

20

 Exhaust system

Number

Designation

Engine 651 in model 172

BA49.10-P-1009-01AI

Bolt, diesel particulate filter bracket to transmission

Nm

39

 Exhaust system

Number

Designation

Engine 651 in model 172

BA49.10-P-1010-01AI

Bolt, clamp to center of exhaust line/diesel particulate filter

Nm

35

 Exhaust system

Number

Designation

Engine 651 in model 172

BA49.10-P-1012-01AI

Bolt, exhaust rubber mount bracket to underfloor/rear axle carrier

Nm

20