Purge valve circuit high.
P0459 — also written PO459, P 0459, 0459 — is the OBD-II code for evap purge control circuit high. Same code, same fix: this page covers every spelling of it.
P0459 means the ECU is seeing too much voltage on the purge valve circuit—usually a shorted solenoid or a chafed wire. We see this constantly on Vauxhall Corsas and Ford Fiestas where the wiring loom rubs against the engine hoist bracket.
P0459 is a emissions fault code, typically costing £45–£260 to put right in a UK garage.
What P0459 actually feels like to drive
- The Engine Management Light (EML) is staring you in the face on the dash.
- A faint smell of petrol vapours around the front wheel arch or under the bonnet.
- The car might struggle to start immediately after you've filled up at the Tesco petrol station.
- Rough idling or 'hunting' when you're sat at the traffic lights.
- A slight dip in your usual MPG as the ECU enters a 'limp' fuel trim mode.
What causes P0459?
- Open circuit
- Failed valve
UK vehicles that throw P0459 most often
- Vauxhall Corsa D/E 1.2 & 1.4 (A12XER/A14XER) 2010-2019
- Ford Fiesta 1.0 EcoBoost (SFJA/SFJB) 2012-2017
- Vauxhall Astra J 1.4 Turbo (A14NET) 2009-2015
- Volkswagen Golf Mk6 1.4 TSI (CAXA) 2008-2012
- Hyundai i10 1.2 Kappa 2008-2013
- Land Rover Freelander 2 3.2 Petrol 2006-2012
How P0459 is fixed
- Replace valve
- Repair wiring
The P0459 misdiagnosis that wastes money
I've seen so many lads just chuck a cheap £15 eBay purge valve at this and then wonder why the light is still on. They assume 'High' means 'High pressure' and start looking for blockages in the charcoal canister. In my experience on the Vauxhall A14NET engines, nine times out of ten it's a broken wire in the loom near the plug or a completely shorted internal coil in the valve itself. People waste money on new fuel caps too, thinking it's an EVAP leak, but P0459 is strictly electrical.
What a UK garage should charge for P0459
For a basic diagnostic plug-in, expect to pay £40-£60 at a local indie. A genuine Bosch or Pierburg purge valve usually costs between £45 and £90 depending on the motor. Fitting is dead simple, usually just half an hour's labour (£40-£50). If you go to a main dealer like Arnold Clark, you’re looking at £120 for the 'diag' alone and probably £250 all-in. Total indie price usually lands around £130-£150 including the VAT.
P0459 repair cost in the UK
Most P0459 repairs land between £45–£260 including parts and labour. The spread is wide because the cheap fix (a sensor, a hose, a leak) and the expensive fix (a major component) throw the same code — which is why a proper diagnosis before parts are bought saves the most money.
Bob's tip on P0459
If you’re taking this to a garage, ask them to do a 'node light' or 'voltmeter' test on the purge valve connector before they buy any parts. If they see a constant 12V when the ECU isn't commanding the valve on, you've got a short to voltage in the loom. Also, insist on a Bosch or Pierburg replacement. The cheap 'white box' parts from the local factor usually have the wrong resistance and will pop the EML again within a week. It’s a 10-minute job to swap, so don't let them charge you an hour's labour.
Can you drive with P0459?
Yes.
Urgency: low.