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
• ◆ VAS 5051 with VAS 5051/1

• or

• ◆ V.A.G 1551 with V.A.G 1551/3 A

Fitting location => Fitting locations overview, Page 24-6

Note:

Checking operation=> Read measured value bloc display group 009, Page 01-129.

Checking for leaks

ACF solenoid valve -N80 remains closed when it is not receiving any current.

• ‒ Disconnect hoses from ACF valve but leave the electrical connector plugged in.
• ‒ Start final control diagnosis and actuate ACF valve.
• ‒ While final control diagnosis is running, blow into solenoid valve to check whether it opens properly. If necessary, fit a new solenoid valve.

Checking internal resistance

• ‒ Unplug connector on ACF valve.
• ‒ → Connect multimeter to valve to measure resistance
• ‒ Specification: 20 ... 28 ω

If the specification is not obtained:

• ‒ Fit a new ACF valve.

Checking power supply

Note:

The ACF valve receives its power supply via the fuel pump relay.

• ‒ Unplug connector on ACF valve.

• ‒ → Connect voltage tester V.A.G 1527 B as follows:

• ‒ Start final control diagnosis => Page 01-75 and actuate fuel pump relay -J17.
• ‒ The LED should light up.

If the LED does not light up:

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

• ● → Check fuse S229 (in fuse holder, position 29).

• ● → Check for open circuit between contact 1 on connector and fuse in fuse holder .

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

• ● Check fuel pump relay => Page 24-43

Checking actuation

• ‒ → Connect voltage tester V.A.G 1527 B between contacts 1 and 2 using auxiliary cables from V.A.G 1594 A.
• ‒ Start final control diagnosis and actuate ACF solenoid -N80.
• ‒ The LED should flash.

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

• ‒ → With the ignition switched off, use adapter V.A.G 1598/12 to connect test box V.A.G 1598 A to connector D only of engine control unit (control unit remains disconnected) => Page 24-17.

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

• ‒ Rectify short circuit or open circuit if necessary.

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

• ‒ If the wiring is OK, fit a new engine control unit => Page 24-20.