P0459: EVAP System Purge Control Valve A Circuit High
A generic powertrain (engine and transmission) trouble code, same meaning on every brand.
Yes - occasional rough idle after refuelling is the usual worst case.
Symptoms
- Check engine light
- Rough idle shortly after filling up
- Slight fuel smell
Likely causes, most common first
- Purge valve circuit shorted to voltage
- Failed purge valve
- Harness damage above the engine
- Corroded connector
Read P0459 yourself before paying for diagnosis
A basic Bluetooth OBD-II scanner ($20-40) plugs into the port under the dashboard and shows this code with live sensor data on your phone - useful both for confirming the fix and for talking to a shop from an informed position.
What is going on and how it gets diagnosed
P0459 reports the purge valve control circuit stuck at high voltage. Together with P0444 and P0445 it forms the family of purge circuit faults, and all three are diagnosed the same way: check for power and ground at the valve, then measure the winding.
One detail is worth knowing before condemning the valve. A purge valve that leaks even slightly when it should be closed lets vapour into the engine at idle, and the fuel trim codes that follow can send diagnosis off in the wrong direction entirely. If lean or rich codes appear alongside this one, the purge valve is the common cause of both.
Repair options and cost
Typical US independent-shop ranges, parts and labor. Dealers run higher; regional labor rates vary.
Frequently asked questions
Can I drive with P0459?
Yes - occasional rough idle after refuelling is the usual worst case.
How much does it cost to fix P0459?
Typical US repair costs range from $80 for the simplest fix (purge control valve) to $400 in the worst case. The right number depends on which cause your car has - see the causes list.
Related codes
The codes closest to P0459. They often appear together, and telling them apart is usually what narrows the diagnosis.
Definition per SAE J2012 standard nomenclature. Symptoms, causes and costs are editorial guidance - always confirm with a diagnosis of your specific vehicle.