Audi Workshop Service and Repair Manuals

Special tools and workshop equipment required

• ◆ V.A.G 1526 A
• ◆ V.A.G 1527 B
• ◆ V.A.G 1594 A
• ◆ V.A.G 1598/31
• ◆ VAS 5051 with VAS 5051/1

Test sequence

• ‒ Connect the vehicle diagnostic, testing and information system VAS 5051 => Page 01-2, and select the vehicle system "01 - Engine electronics" from the menu. When doing this the engine should be idling.

• ‒ Select "Read data block", Display Group 018, engine idling

→ Display on VAS 5051:

• ‒ Specification: "0" in all 4 display zones for correct control
• Press the ◂ button to exit from the function "08 - Read data block".
• Select diagnosis function "06 - End output".

If the display shows a reading other than "0".

• ‒ Test activation.

Checking activation

• ‒ Connect test box V.A.G 1598/31 to wiring harness for engine control unit and to engine control unit => Page 23-37.

• ‒ Connect voltage tester V.A.G 1527 B as follows:
• ‒ Operate starter briefly.

If the specifications are not obtained:

• ‒ Test the wiring => Page 23-25.

If the specifications are obtained:

Testing internal resistance

• ‒ Connect test box V.A.G 1598/31 to wiring harness for engine control unit. Do not connect to the engine control unit itself.
  => Page 23-37.

• ‒ Connect multimeter (resistance test range) as follows:

Note:

The specification of approx 0.5ωapplies to a measurement taken directly at the solenoid valve of the unit injector. With the measuring method used here, the wiring resistance has to be added to this figure, so that the reading will always be 0.3 ... 0.5 ω above the specified value.

If the specification is exceeded considerably or if the reading is 0 ω or ∞ ω::

• ‒ Remove cylinder head cover

=> 4-Cyl diesel direct injection engine (TDI); Repair group 15; Removing and installing cylinder head; Removing and installing cylinder head cover

• ‒ → Lever connector off unit injector with a screwdriver -arrow-. Support the opposite side of the connector with light finger pressure to stop it from jamming.

• ‒ → To measure internal resistance, connect multimeter directly to unit injector solenoid valve with connector disconnected (resistance measurement range).
• ‒ Specification: approx. 0.5 ω

If the specification is not attained:

• ‒ Replace unit injector

If the specification is obtained:

Testing wiring

• ‒ Connect test box V.A.G 1598/31 to wiring harness for engine control unit. Do not connect to the engine control unit itself.
  => Page 23-37.
• ‒ → Test for open circuit and short to positive or earth in the following wiring connections:

If no fault is found:

• ‒ Fit a new engine control unit => Page 23-40.