P0459: EVAP purge control valve circuit high
The ECU sees too high a voltage in the purge valve circuit. It is usually a broken wire, a loose connector or the valve itself.
| Code | P0459 |
|---|---|
| System | Engine and transmission |
| Group | P04xx, Emissions control |
| Type | Generic: it means the same on every make |
| Can you keep driving? | With care |
What P0459 means
The purge valve lets the engine draw petrol vapour from the canister when appropriate. The ECU switches it open and shut and monitors its circuit. Circuit high means it sees a voltage above what should be possible, typical of an open circuit or a wire touching a live feed.
Most common causes
- Purge valve connector unplugged or with loose pins
- Control wire broken (open circuit)
- Bare wire touching a positive feed
- Open circuit inside the valve coil
- Rarely, an ECU fault
Symptoms
- Engine warning light on
- Usually no change in how it drives
- Sometimes a petrol smell or slightly higher fuel use
Can you drive with P0459?
With care You can drive, but get it fixed soon: without purging, the canister fills up and more EVAP faults may follow.
How to check it
Unplug the valve and measure its resistance with a multimeter, then compare it with the maker’s figure. If it is fine, the fault lies in the wiring or connector.
How to read and clear P0459 with Final OBD
Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see P0459 with this same explanation and whether it’s confirmed, pending or permanent.
With Free you read this code with its short description for nothing, and clear it if the engine stores it over standard OBD. With Pro you get the full explanation, how the car was running when it was logged (revs, temperature, load) and clearing in every control unit.
Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before the ITV. It’s all in how to read and clear fault codes and in the ITV and OBD.
Similar codes
- P0455 EVAP system large leak detected
- P0456 EVAP system very small leak detected
- P0457 EVAP system leak: fuel cap loose or missing
- P0458 EVAP purge control valve circuit low
- P0460 Fuel level sensor circuit malfunction
- P0461 Fuel level sensor circuit range/performance
- P0462 Fuel level sensor circuit low input
- P0463 Fuel level sensor circuit high input
- P0400 Exhaust gas recirculation (EGR) flow malfunction
- P0401 Exhaust gas recirculation (EGR) flow insufficient
- P0402 Exhaust gas recirculation (EGR) flow excessive
- P0403 EGR control circuit malfunction
P0459 is a generic code, so it means the same on any make, for example on Citroën, Hyundai, Mercedes-Benz, Mini, Renault, Volvo. See what Final OBD does on your car in makes and models.
What does code P0459 mean?
The purge valve lets the engine draw petrol vapour from the canister when appropriate. The ECU switches it open and shut and monitors its circuit. Circuit high means it sees a voltage above what should be possible, typical of an open circuit or a wire touching a live feed.
Can you drive with P0459?
You can drive, but get it fixed soon: without purging, the canister fills up and more EVAP faults may follow.
How do you clear P0459?
With an OBD2 scanner and an app like Final OBD, which clears it for free if it’s stored by the engine control unit. But clearing it only turns the light off: if the cause isn’t fixed, P0459 comes back.
Read it on your car
Final OBD reads the faults of every control unit for free, including each make’s own codes, and with Pro explains each one in plain English. Free clears engine faults at no cost.
Coming soon
Mid to late October 2026
If you want to try it in your car before anyone else, send us your email and we will add you as a tester.
info@finalobd.com