Remove/install engine control (MR) control unit

AR07.15-W-1630S

Remove/install engine control (MR) control unit

21.04.2017

Engine

457.9 in model 949

1

Electrical connection (engine wiring harness)

4

Fuel heat exchanger

7

Hand pump

2

Electrical connection (vehicle wiring harness)

5

Guide tube

8

Rubber shock absorbers

3

Fuel line

6

Bracket

A6

Engine control (MR) control unit

 Warning

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 buttoned-up and snug-fitting work clothes. Do not touch hot or rotating parts.

AS00.00-Z-0005-01A

 Danger

Risk of explosion caused by fuel igniting, risk of poisoning caused by inhaling and swallowing fuel as well as risk of injury to eyes and skin caused by contactwith fuel.

No fires, sparks, open flames or smoking. Pour fuels into suitable and appropriately marked containers only.
Wear protective clothing when handling fuel.

AS47.00-Z-0001-01A

Topical note

Information on preventing damage to electronic components due to electrostatic discharge

AH54.00-P-0001-01A



Remove

1

Switch off ignition

2

Open engine hood and raise to vertical position

AR88.40-W-1000R

3

Remove front section of fender on the left

AR88.10-W-1500RE

4

Remove exhaust pipe of stationary heater

Only for vehicles with code H65 ("Webasto" Thermo Top 90 warm water auxiliary water heater).

5

Remove fuel line (3) on fuel heat exchanger (4)

 Allow escaping fuel to drain into a suitable container.

6

Remove hand pump (7) on fuel heat exchanger (4)

7

Disconnect electrical connection (vehicle wiring harness) (2) from engine control (MR) control unit (A6)

8

Disconnect electrical connection (engine wiring harness) (1) from engine control (MR) control unit (A6)

9

Remove engine control (MR) control unit (A6) with rubber dampers (8) and remove upwards

10

Remove fuel heat exchanger (4) from engine control (MR) control unit (A6)

Only if the engine control (MR) control unit (A6) is replaced.



Install

11

Attach fuel heat exchanger (4) to engine control (MR) control unit (A6)

Only if the engine control (MR) control unit (A6) is replaced.

 Bolt, fuel-heat exchanger to engine control (MR) control unit

*BA07.15-N-1001-01G

12

Attach engine control (MR) control unit (A6) with the damper rubber (8)

 First place screw/bolt at the upper right.

 Bolt, engine control (MR) control unit to crankcase

*BA07.15-N-1002-01G

13

Connect electrical connection (engine wiring harness) (1) to engine control (MR) control unit (A6)

14

Disconnect electrical connection (vehicle wiring harness) (2) from engine control (MR) control unit (A6)

15

Attach hand pump (7) to fuel heat exchanger (4)

 Banjo bolt, hand pump to fuel heat exchanger

*BA47.25-N-1019-01M

16

Attach fuel line (3) to fuel heat exchanger (4)

 Install new sealing rings.

 Banjo bolt, fuel line to fuel heat exchanger

*BA47.25-N-1009-01M

17

Install exhaust pipe for stationary heater

Only for vehicles with code H65 ("Webasto" Thermo Top 90 warm water auxiliary water heater).

18

Install front section of fender on the left

AR88.10-W-1500RE

19

Teach-in transponder key again and also replacement key

Only if engine control (MR) control unit (A6) was replaced.

AR80.57-W-0010C

20

Start the engine, bleed fuel system and perform engine test run

 The fuel system is bled automatically.

If engine fails to start or only runs for a brief period.



Purge fuel system by hand.

AR47.00-W-1720S

21

Turn off the engine and check in area of the engine control (MR) control unit (A6) for leaktightness

 Visual inspection.

22

Close engine hood

AR88.40-W-1000R

 Diesel injection system with unit pumps (MR)

Number

Designation

Engine 457.9

BA07.15-N-1001-01G

Bolt, fuel-heat exchanger to engine control (MR) control unit

Nm

8

 Diesel injection system with unit pumps (MR)

Number

Designation

Engine 457.9

BA07.15-N-1002-01G

Bolt, engine control (MR) control unit to crankcase

Nm

12

 Fuel lines/hoses

Number

Designation

ENGINE 457.9

BA47.25-N-1009-01M

Banjo bolt, fuel line to fuel heat exchanger

Nm

50

 Fuel lines/hoses

Number

Designation

ENGINE 457.9

BA47.25-N-1019-01M

Banjo bolt, hand pump to fuel heat exchanger

Nm

50