Testing solenoid valve 1 for activated carbon filter. — AUDI
Testing solenoid valve 1 for activated carbon filter. on Audi: factory workshop procedure for engines AEH, AKL. Full factory text, tools and checks.
Workshop procedure for AUDI — the factory write-up, straight from real workshop data.
📐 23 workshop diagrams for AEH
Real factory drawings for this job — timing marks, bolt locations and routing. Locked in the free view.
📋 Procedure
AKL
Testing for leaks
When there is no electrical signal the solenoid valve remains closed.
Disconnect hose from the solenoid valve for the activated carbon filter (N80).
Start final control diagnosis and select solenoid valve for activated carbon filter (N80)
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While final control diagnosis is running, blow into solenoid valve to check whether it opens and closes properly. If necessary, fit a new solenoid valve.
Electrical test of -N80 (ACF valve)
Unplug connector on ACF valve.
Measure resistance between contacts on valve using hand held multimeter V.A.G 1526.
Specification: 22...30 ω.
If the value is not as specified, fit a new ACF valve.
Testing power supply to ACF valve
Note:
The ACF valve receives its power supply via the fuel pump relay.
Test conditions
Fuse for ACF 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.
Specification: The diode test lamp should light up.
If diode test lamp does not light up, test for open circuit between contact 1 and fuse. Rectify open circuit if necessary.
=> Current Flow Diagrams, Electrical Fault Finding and Fitting Locations
If wiring is OK, test fuel pump relay => Page
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Testing ACF valve activation
Connect diode test lamp V.A.G 1527 between contact 2 (earth connection via engine control unit) and contact 1 (positive, from fuel pump relay) on the connector.
Start final control diagnosis and select solenoid valve for activated charcoal filter (N80)
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Specification: diode test lamp should start flashing.
If the diode test lamp does not flash or lights up continuously:
Switch off ignition.
Connect test box V.A.G 1598/22 to wiring harness for engine control unit
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If the diode test lamp lights up continuously, test for short circuit to earth in wiring between contact 2 on ACF valve connector and socket 15 on test box.
If the diode test lamp does not flash, test for open circuits and short circuits to positive in the wiring between contact 2 on ACF valve connector and socket 15 on test box.
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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TorqFix answers live for your specific car — tell it the engine code and it serves the matching sequence, torque figures and wiring for that exact variant.
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Who makes these pages, and how
TorqFix was built by a mechanic — after a 2,700 km drive with five roadside repairs that no diagnostic tool could explain.
The figures on this page come from manufacturer workshop documentation and are shown as they are. The page is assembled automatically from that data — it is not written by an AI. The AI works in the chat, where it answers for your specific car. It writes nothing here.
Variants of the same model differ. Cross-check torque against the factory manual for your engine before final tightening.
Seen a figure that does not match your manual? Write to us — we correct it and note when. support@torqfix.com
The story behind TorqFix →Workshop data on this page last updated 20 Sep 2026.