Audi Workshop Service and Repair Manuals

Special tools,
testers and equipment required

• ◆ V.A.G 1526 A
• ◆ V.A.G 1527 B
• ◆ V.A.G 1594 A
• ◆ V.A.G 1598 A
• ◆ V.A.G 1598/11
• ◆ VAS 5051 with VAS 5051/1

• or

• ◆ V.A.G 1551 with V.A.G 1551/3 A

Note:

On vehicles with no air conditioner, voltage is applied to contact 11 of engine control unit wen heated rear window is switched on. This increases the idling speed for a higher charging rate.

• ‒ Reading measured value block, display group 004, engine at idling speed .

• ‒ Check display in display zone 4.
• ‒ Specification: 0XX XX

Note:

Switching inputs at locations marked "X" can be ignored for this test.

• ‒ Switch off the heated rear window.
• ‒ Specification: 1XX XX

If the displays are not as described:

• ‒ → With the ignition switched off, use adapter V.A.G 1598/11 to connect test box V.A.G 1598 A to connector C only of engine control unit (control unit remains disconnected) .
• ‒ Connect voltage tester V.A.G 1527 B as follows:

• ‒ Switch on ignition and heated rear window.
• ‒ The LED should light up.

If the LED does not light up:

• ‒ Pull connector C off engine control unit.

If the LED then lights up:

• ‒ Fit a new engine control unit => Page 24-20.

If LED still does not light:

• ‒ Check for open circuit and short to positive or earth in the following wiring connections:

If the wiring is OK:

• ‒ Check the heated rear window.