Testing solenoid valve 1 for activated charcoal filter — AUDI

AZB
Note:

Solenoid valve 1 for the activated charcoal filter system is also referred to in this context as fuel tank breather valve.

Testing for leaks

When there is no electrical supply, solenoid valve remains closed.

Disconnect hoses from solenoid valve for activated charcoal filter (N80).
Start final control diagnosis and select solenoid valve for activated charcoal filter (N80)
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Final control diagnosis
⇒
Tank breather valve -N80
Indicated on display:

The valve should click...
...and should open and close (check by blowing into the auxiliary hose).

If the valve does not click, electrically check solenoid valve 1 for activated charcoal filter => Page
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If the valve does not open and close correctly, renew solenoid valve 1 for activated charcoal filter.

Electrical check for solenoid valve 1 for activated charcoal filter -N80

Unplug connector on ACF valve.
Measure resistance between contacts on valve using hand-held multimeter V.A.G 1526.

Specification: 22...30 Ohms

If specification is not attained:

Replace -N80 solenoid valve for activated charcoal filter.

If specification is attained, check voltage supply => Page
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Checking solenoid valve voltage supply

Note:

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

Test conditions

Fuse for activated charcoal filter valve OK

Unplug connector on ACF valve.
Connect diode test lamp V.A.G 1527 between engine earth and contact 1 on the connector.
Operate starter.

The diode test lamp should light up.

If the diode test lamp does not light up:

Check the wiring from contact 1 via the fuse to the fuel pump relay for continuity, repair if necessary.

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

If wiring is OK, test fuel pump relay => Page
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If diode test lamp illuminates, check activation => Page
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Testing ACF valve activation

Connect the V.A.G 1527 diode test lamp between contact 2 and contact 1 (positive) in the connector.
Start final control diagnosis and select solenoid valve for activated charcoal filter (N80)
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Diode test lamp should flash.

If the diode test lamp does not flash or is continuously lit:

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
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If the diode test lamp is continuously lit:

Test for the line from contact 2 on the ACF valve connector and socket 64 on the test box for a short to earth.

If the diode test lamp does not flash:

Check line from contact 2 on activated charcoal filter valve connector to contact 64 on test box for continuity and for short to positive.

Wire resistance: max. 1.5 Ohm

If necessary, rectify short circuit to earth or open circuit.
If no short circuit or open circuit is found, fit a new engine control unit
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