The evaporative-emissions system handles fuel vapour. P0443 concerns the purge-valve circuit, P0444 an open circuit and P0445 a shorted circuit. These are useful distinctions when an engine warning is being investigated; a fuel-cap check alone does not establish the condition of a valve’s electrical circuit.
Keep the fault description intact
A scan may include a leak or flow code as well as an electrical entry. Save both. Record starting problems after refuelling, unusual idle behaviour and whether the warning appeared after work around the intake or wiring. These observations guide testing but are not a diagnosis by themselves.
For the VAG N80 purge valve, Ross-Tech’s P0444 reference identifies the fuse, valve and open wiring/connections as possible causes. P0444 technical reference.
What a workshop needs to establish
- Correct power supply and circuit protection for the actual vehicle.
- Valve and connector condition under the specified checks.
- Whether the controller’s command reaches the component.
- Whether the electrical fault is separate from any vapour-flow problem.
Fuel-vapour work requires suitable precautions and equipment. Do not bypass emissions components or use improvised energising tests. If there is a strong fuel smell or a suspected fuel leak, arrange a safe inspection.
AXION electrical enquiries
Send the existing scan and circuit findings through our contact page. If ECU output testing is being considered, include the component specification and wiring results so the assessment has a clear purpose. Browse the repair library for related electrical topics.
Reviewed September 2026. Use the complete manufacturer-specific fault description and vehicle repair information.