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.
Open the bonnetthe in-depth explanation
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 its description and whether it’s confirmed, pending or permanent.
If the engine stores it over standard OBD, with FREE you read this code with its explanation for nothing and clear it. With PRO you also read the faults of every control unit and clear them in all of them.
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 an inspection. It’s all in how to read and clear fault codes and in inspections 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
- P045A The exhaust gas recirculation B control has an electrical fault
- P045B The exhaust gas recirculation B control gives readings outside the normal range
- P045C The exhaust gas recirculation B control gives a lower signal than normal
- P045D The exhaust gas recirculation B control gives a higher signal than normal
- 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
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 and clears engine faults through standard OBD for free, each one explained in plain English. With PRO it also reads the faults of every control unit, each make’s own codes included, and clears them in all of them.
