Audi Workshop Service and Repair Manuals

Special tools, testers 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

• or

• ◆ V.A.G 1551 with V.A.G 1551/3 A

Installation position => Overview installation positions - Page 24-5

Test requirements:

• ● Final control diagnosis has been performed

Checking internal resistance

• ‒ Unplug connector from intake manifold changeover valve -N156.
• ‒ → Connect multimeter to valve to measure resistance
• ‒ Specified value: 25 ... 35 ω
• ‒ If the reading does not match the specified value, replace intake manifold changeover valve -N156.

Checking voltage supply

• ‒ Unplug connector from intake manifold changeover valve -N156.
• ‒ → Connect voltage tester V.A.G 1527 B as follows:

• ‒ Operate starter briefly.
• ‒ The LED should light up.

If the LED does not light up:

• ‒ Carry out the following tests (marked with dots):

• ● → Check fuse S234 (in fuse holder, position 34).

• ● → Check for open circuit between contact 1 of plug and fuse S234 (in fuse box position 34).

=> "Current Flow Diagrams, Electrical Fault Finding and Installation locations" binder

• ● Check fuel pump relay .

Checking actuation

• ‒ → Connect up voltage tester V.A.G 1527 B between contacts 1 and 2.
• ‒ Start final control diagnosis and actuate the intake manifold changeover valve.
• ‒ The LED should flash.

If the LED lamp does not flash or if it lights up continuously:

• ‒ Connect the V.A.G 1598/31 test box to wiring harness leading to engine control unit; the engine control unit should not be connected => Page 24-20.

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

• ‒ Rectify any open/short as necessary.

=> "Current Flow Diagrams, Electrical Fault Finding and Installation locations" binder

If the wiring is OK:

• ‒ Replace engine control unit => Page 24-23.