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

• or

• ◆ V.A.G 1551 with V.A.G 1551/3 A

Fitting location => Fitting locations overview, Page 24-5

Test requirements:

• ● Final control diagnosis has been performed
• ● Fuse for intake manifold change-over valve OK

=> Current Flow Diagrams, Electrical Fault-Finding and Fitting Locations

• ● Check pump relay OK; checking .

Checking internal resistance

• ‒ Unplug connector from intake manifold changeover valve -N156.

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

Checking power 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:

• ‒ Check the wiring from contact 1 on the connector via the fuse to the fuel pump relay for an open circuit.

=> Current Flow Diagrams, Electrical Fault-Finding and Fitting Locations

Checking actuation

• ‒ → Connect voltage tester V.A.G 1527 B between contacts 1 and 2.
• ‒ Initiate the final control diagnosis and activate 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 24-17.

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

• ‒ Rectify any open/short circuit as necessary.

=> Current Flow Diagrams, Electrical Fault-Finding and Fitting Locations

If the wiring is OK:

• ‒ Fit a new engine control unit => Page 24-22.