Replace gas pressure regulator and change data record in engine control (MR) control unit

SM07.54-W-0003A

Replace gas pressure regulator and change data record in engine control (MR) control unit

16.11.09

Category

Op. no.

Operation text

Time

Acc. no.

Code

O

027069

OPERATIONS: CHANGE DATA RECORD AND SOFTWARE IN MR CONTROL UNIT

0,7h

47 920 54

GAS CONTROL

O

027070

OPERATIONS: REPLACE CAP OF ELECTRONIC ACCELERATOR ADJUSTING MOTOR

0.1 h

47 920 54

GAS CONTROL

O

027071

OPERATIONS: CHECK INSTALLATION OF LINES OF OXYGEN SENSOR

0.1 h

47 920 54

GAS CONTROL

O

027072

OPERATIONS: REPAIR INSTALLATION OF LINES OF OXYGEN SENSOR

0.1 h

47 920 54

GAS CONTROL

O

027073

OPERATIONS: CHECK GAS INJECTION VALVES

0.8 h

47 920 54

GAS CONTROL

O

027074

OPERATIONS: MODIFY GAS INJECTION VALVE (1)

0.2 h

47 920 54

GAS CONTROL

O

027075

OPERATIONS: MODIFY GAS INJECTION VALVE (EACH REMAINING)

0.2 h

47 920 54

GAS CONTROL

O

027076

OPERATIONS: REPLACE GAS PRESSURE REGULATOR

1,2h

47 920 54

GAS CONTROL



Checking

1

Close gas shutoff valves at compressed-gas tanks

AR47.10-W-0005H

 Danger!

Risk of accident caused by vehicle starting off by itself when engine is running. Risk of injury caused by contusions and burns during starting procedure or when working near the engine as it is running

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

AS00.00-Z-0005-01A

2

Start engine and run on idle until the engine goes off by itself

 In this way residual gas is used up in the lines and components.

3

Switch off ignition

4

Remove cylinder head cover (3)

AR01.20-W-5014H

5

Check part number of gas injection valves

 Gas injection valves, which do not have the part number A 906 078 04 49, should be replaced:



Replace gas injection valve.

AR07.54-W-0003H

 With regard to return shipment or scrapping of removed parts, please observe the information in your warranty system.

6

Check gas injection valves for firm seating in intake manifold

 If loose gas injection valves are detected:



Remove corresponding gas injection valve, insert shim in the valve seat and install gas injection valve again.

AR07.54-W-0003H

7

Install cylinder head cover (3)

 Only tilt back the cab after replacing the gas pressure regulator.

AR01.20-W-5014H

8

Replace cap (4) on electronic accelerator adjusting motor

9

Check routing of electrical line (1) to oxygen sensor

 If the installation of lines does not correspond to the figure or the insulation of the electrical line (1) is damaged:



Insulate electrical line (1), route over the intake manifold (6) and secure with cable ties (2).

10

Replace gas pressure regulator

 The manufacturer's serial number of the previous (removed) and new gas pressure regulator must be entered in the message field of the warranty claim.

AR07.17-W-0001H

With regard to return shipment or scrapping of removed parts, please observe the information in your warranty system.

11

Connect Star Diagnosis

 The download is available as of Star Diagnosis DAS update 11/2009.

 The following conditions must be met for carrying out the download:

- Battery voltage 24 V...26 V.

- It is essential that the power supply for the STAR DIAGNOSIS computer remains constant throughout the entire period.

During the download, do not

- Start any other application,

- Perform on-board diagnosis,

- Run or start the engine and

- Disconnect the vehicle battery.

12

Switch on ignition

13

Start Diagnosis Assistance System (DAS)

14

Select "Truck" category

15

Select "Automatic access using model series"

16

Select "Special functions"

17

Select "CNG [compressed natural gas] download"

18

Select the download with the highest number

 The download is menu-assisted. Follow all of the instructions given by the Diagnosis Assistance System (DAS).

With the display "The control unit already contains the latest control unit software version" the latest version is already installed and the process is complete.

Likewise the process is complete if the display "The control unit programming has been carried out successfully." appears.

19

Disconnect Star Diagnosis

Part no.

Designation

Quantity

A 906 078 04 49

Gas injection valve

As required

A 126 262 10 52 05

Washer

As required

A 000 998 69 21 05

Cap

1

A 001 476 17 32 05

Gas pressure regulator

1