Test sequence

Checking the function of the injection timing control range is accomplished in function 04 (Basic settings). Using this procedure, the cold start injector is pulsed so that the range of values for the advanced and retarded positions of the injection timing device can be read in display field 3.

• Connect Scan Tool VAG 1551 ((VAG 1552) and select engine electronics control unit with the "Address word" 01. When doing this the engine must be running at idling speed. (Connecting Scan Tool and selecting engine electronics control unit; see VAG 1551 SCAN TOOL, CONNECTING .)

Indicated on display:

• Press buttons -0- and -4- to select "Basic setting" function 04 and confirm entry with -Q- button.

Indicated on display:

• Press buttons -0-, -0- and -4- for "Display group number 4" and confirm entry with -Q- button.

Indicated on display:

Specification in display field 3: advanced 7.0 to 9.0 ° BTDC

After approx. 10 seconds the timing device is moved to the retarded (late) position.

Indicated on display:

Specification in display field 3: retarded 3.0 to 5.0 ° BTDC

If the specifications are not obtained:

• Check commencement of injection valve as follows:
• Press the --> button.
• Press buttons -0- and -6- to select "End output" and confirm entry with the -Q- button.
• Switch off ignition.
• Disconnect the 10 -pin connector for the quantity adjuster (connector to quantity adjuster in injection pump) -arrow-.
Fig 5: Disconnecting Pin Connector For Quantity Adjuster
Courtesy of VOLKSWAGEN OF AMERICA, INC.
• Measure resistance between connector contacts 9+10.

  Specification: 12 to 20 Ω

Fig 6: Identifying 10-Pin Connector Terminals
Courtesy of VOLKSWAGEN OF AMERICA, INC.

If the specification is not obtained:

• Replace Cold Start Injector -N108, see Injection pump, servicing .
• Check DTC memory and, if necessary, repair any malfunctions and then erase; see DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING AND ERASING .
• Read-out the readiness code, see READING READINESS CODE . If the DTC memory has been erased or the Diesel Direct Fuel Injection Engine Control Module - J248- was disconnected from permanent battery positive (B+), the readiness code must be generated again; see READINESS CODE, SETTING .

If the specification is obtained:

• Remove wiper arms and plenum cover:

  See Plenum Cover Emoval & Installation

• Connect test box VAG 1598/31 to control unit wiring harness.
Fig 7: Connecting Test Box VAG 1598/31 To Control Unit Wiring Harness
Courtesy of VOLKSWAGEN OF AMERICA, INC.
• Check wiring between test box and 10 -pin connector for open circuit according to wiring diagram.

  Terminal 9+ socket 114

  Terminal 10+ sockets 1 and 2

  Wire resistance: max. 1.5 Ω

Fig 8: Identifying 10-Pin Harness Connector Terminals
Courtesy of VOLKSWAGEN OF AMERICA, INC.
• Check wires for short to one another, to vehicle Ground and to battery positive (B+).

  Specification: Ω

If no fault is detected in the wiring:

• Replace Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) -J248-, see DIESEL DIRECT FUEL INJECTION (DFI) ENGINE CONTROL MODULE .