Very common code — the fuel cap isn't sealing.
P0457 — also written PO457, P 0457, 0457 — is the OBD-II code for evap leak detected — fuel cap loose. Same code, same fix: this page covers every spelling of it.
This is the car's computer telling you it can't pressurise the fuel system properly, usually because the fuel cap is loose, cross-threaded, or the seal has perished. It’s a very common 'nuisance' code on Vauxhalls and Fords.
P0457 is a emissions fault code, typically costing £0–£60 to put right in a UK garage.
What P0457 actually feels like to drive
- Engine management light (EML) glowing amber on the dash.
- A distinct smell of petrol fumes when walking past the rear of the car.
- The light popped on shortly after a trip to the Tesco or Shell pump.
- A slight 'hissing' sound missing when you unscrew the cap to refuel.
- Failed MOT if the tester spots the EML or detects a fuel leak.
What causes P0457?
- Loose or cross-threaded fuel cap (very common)
- Damaged cap seal
- Worn filler neck
UK vehicles that throw P0457 most often
- Vauxhall Corsa D/E 1.2 & 1.4 (2006-2019)
- Ford Fiesta Mk7 1.25 Zetec (2008-2017) (Capless 'EasyFuel' issues)
- Vauxhall Astra J 1.4 Turbo (A14NET)
- Honda Civic 1.8 i-VTEC (2006-2012)
- Ford Focus Mk3 1.6 Ti-VCT (2011-2018)
- Fiat 500 1.2 Petrol (2008-present)
How P0457 is fixed
- Tighten fuel cap for 3 drive cycles
- Replace cap seal or cap
The P0457 misdiagnosis that wastes money
I’ve seen dozens of lads rush to swap out the purge valve or the charcoal canister the second they see an EVAP leak code. They spend £150 on Bosch parts when the actual fault is a £1.50 rubber O-ring on the petrol cap that's gone rock hard and cracked. Another classic is the filler neck itself; on older Corsas and Fiestas, the neck can actually rot out from road salt spray, meaning no matter how tight that cap is, the tank won't hold a vacuum. Check the simple stuff before you start ripping the fuel system apart.
What a UK garage should charge for P0457
If it's just a loose cap, most local indy shops will clear the code for a 'drink' or a minimum diagnostic fee of £30-£45. A genuine replacement cap for a Vauxhall or Ford usually sits around £20-£35 from a factor like Euro Car Parts or GSF. If the filler neck is rusted through, you’re looking at £150-£220 including labour. A main dealer will easily double these prices just for the 'privilege' of the coffee in the waiting room.
P0457 repair cost in the UK
Most P0457 repairs land between £0–£60 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 P0457
If your light is on, don't just clear it and hope. Inspect the rubber seal on your fuel cap for 'cracking' or perishing. If you buy a replacement, for heaven's sake, don't buy a £5 universal one from a petrol station forecourt—they never seal right and the light will be back in two days. Insist your garage does a 'smoke test' if the cap looks fine. We pump theatrical smoke into the EVAP lines; if we see a puff coming from the wheel arch or the tank top, we’ve found your leak without guessing.
Can you drive with P0457?
Yes.
Urgency: low.