Quantity Adjuster Control Range

The control range of the fuel injection quantity adjuster can be checked via Function 03: Output Diagnostic Test Mode (DTM) and at the same time calling-up measuring value block 04. Activate Output DTM component start of injection valve N108, then exit the Output Diagnostic Test Mode using button -C-. Using this sequence, the start of injection valve continues to be pulsed so that with help of measuring value block 04 (display zone 3) the quantity adjuster control range can be displayed.

Special Tools, Testers And Auxiliary Items:
- VAG 1551/1552 Scan Tool with VAG 1551/3 adaptor cable
- VAG 1598/18 Test Box
- Fluke 83 multimeter (or equivalent)
- VW 1594 adaptor kit
- Wiring diagram

Testing Procedure:
- Connect VAG 1551/1552 Scan Tool
- Start engine and let idle
- Press 0 and 1 buttons to select address word 01 "engine electronics"
Display will appear as shown:

Rapid data transfer HELP
select function XX

- Press 0 and 3 buttons to select Function 03 "Output Diagnostic Test Mode"
- Press Q button to enter input
Display will appear as shown:

Rapid data transfer Q
03 Output Diagnostic Test Mode

NOTE: Individual DTM components are activated for 30 seconds. Various work sequences must be carried out with the Scan Tool within this period as well as reading the displayed values. Read over the following work sequence first to familiarize yourself with the procedure.

- Press Q button
Display will appear as shown:

Output Diagnostic Test Mode ->
start of injection valve - N108

- press C button
- Press 0 and 8 buttons to select Function 08 "Read measuring value block"
- Press Q button to enter input
Display will appear as shown:

Read measuring value block HELP
Input display group number XXX

- Press 0, 0 and 4 buttons to select "display group 4"
- Press Q button to enter input
Display will appear as shown:

Read measuring value block 4 ->
840 rpm 0.9°BTDC 0.9° BTDC 3%

NOTE: The displays in display zones 3 and 4 must fluctuate within following control range:
- Specification display zone 3
lower range: 1° ATDC to 4.0° BTDC.
upper range: 14.0 to 17.4° BTDC.
- Specification display zone 4
lower range 2 to 5%.
upper range 90 to 95%.
Due to the slow refresh rate of the VAG 1551 Scan Toot the displayed values can greatly vary Ensure that the lowest value only in display zone 3 lies between 1.0 and 4.0 and the nighest value lies between 14.0 and 174. Ensure that the lowest value in display zone 4 lies between 2 and 5, and the highest value between 90 and 95.

If specifications not obtained:
- Check start of injection valve as follows
- Press -> button
- Press 0 and 6 buttons to select function 06 "End data transfer"
- Press Q button to enter input
- Switch OFF ignition
- Disconnect Diesel injection pump harness connector





- Measure resistance between connector terminals 2 + 3:
Specification: 12 to 20 Ohms.

If specification not obtained:
- Replace start of injection valve N108
- Display the readiness code

If DTC memory was erased:
- Create readiness code again

If specification obtained:





- Connect Test Box VAG 1598/18 to ECM harness connector





- Check wiring for open circuit between Test Box and 3 pin connector using wiring diagram:
terminal 2 + socket 51
terminal 3 + socket 68
Wire resistance: max. 1.5 Ohms.

- Additionally check wires for short to one another
Specification: Infinite Ohms.

If wiring OK:
- Replace Diesel direct injection system ECM J248
- Display the readiness code

If DTC memory was erased:
- Create readiness code again