Audi Workshop Service and Repair Manuals

Leak test

Solenoid valve is closed when de-energised.

• ‒ Pull hoses off activated charcoal filter solenoid valve 1 -N80.
• ‒ Connect test hose to one connection of ACF valve.
• ‒ Connect vehicle diagnostic, testing and information system VAS 5051 or fault reader V.A.G 1551 and select engine electronics control unit with "address word" 01 .
  Engine must be idling.
• ‒ Start final control diagnosis and select activated charcoal filter solenoid valve -N80 (fuel tank breather valve) .

• Solenoid valve must click...
• ...and must open and close (can be checked by blowing into test hose).

• ‒ If valve does not click, perform electrical check on activated charcoal filter solenoid valve 1 => Page 24-133.
• ‒ If valve does not open and close properly, replace activated charcoal filter solenoid valve 1.

Electrical check on activated charcoal filter solenoid valve -N80

• ‒ Unplug connector from activated charcoal filter solenoid valve -N80.
• ‒ → Measure resistance with portable multimeter V.A.G 1526 between contacts of solenoid valve.

• Specification: 22...30 ohms

If reading does not match specification:

• ‒ Replace activated charcoal filter solenoid valve -N80.

If reading matches specification:

• ‒ Check power supply => Page 24-134.

Checking solenoid valve power supply

Note:

Activated charcoal filter solenoid valve is supplied with power by way of fuel pump relay.

Test requirement

• ● Fuse for activated charcoal filter solenoid valve OK

• ‒ Unplug connector from activated charcoal filter solenoid valve -N80.
• ‒ → Connect diode test lamp V.A.G 1527 between socket 1 of connector and engine earth.
• ‒ Operate starter.

Diode test lamp must light.

If diode test lamp does not light:

• ‒ Check for continuity in wiring from socket 1 via fuse to fuel pump relay and repair if necessary.

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

• ‒ If wiring is OK, check fuel pump relay => Page 24-47.

If diode test lamp lights, check actuation => Page 24-135.

Checking actuation of activated charcoal filter solenoid valve

• ‒ → Connect diode test lamp V.A.G 1527 between sockets 1 (positive) and 2 of connector.
• ‒ Start final control diagnosis and select activated charcoal filter solenoid valve -N80 .

Diode test lamp must flash.

If diode test lamp does not flash or if it is permanently lit:

• ‒ Connect test box V.A.G 1598/31 to engine control unit wiring harness. Actual engine control unit is not to be connected.

If diode test lamp is permanently lit:

• ‒ Check for short to earth in following wiring.

If diode test lamp does not flash:

• ‒ Check for short to positive/open circuit in the following wiring.

• Resistance: max. 1.5 ohms

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

• ‒ If necessary, eliminate earth connection/open circuit in wiring.
• ‒ If there is neither an open circuit in the wiring nor a short circuit:
• ‒ Replace Motronic control unit -J220 => Page 24-16.