P0457 code meaning
EVAP System Leak Detected (fuel cap loose/off)
Powertrain system Generic code P04xx codes Check engine light
What P0457 means
The evaporative emission (EVAP) system stores fuel vapour from the tank in a charcoal canister; a purge valve lets the engine draw it off, and a vent valve opens the canister to fresh air. P0457 is a large leak attributed to the fuel cap: Ford detects refuelling and treats a vacuum that is not reached afterwards (about −2 kPa in 30 s) as an open cap. CARB allows a separate check fuel cap lamp instead of the warning lamp, and the code is cleared once the cap is found tight again. Ford sets the lamp after two to three trips depending on calibration, Subaru after two. GM and Saab's ME9 do not use the code.
P0457 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyEasy, DIY possible
- Typical labor0 to 0.5 hours
- Clears after repairAfter a drive cycle
Symptoms of P0457
- Check fuel cap lamp or check engine light on
- Fuel smell
- EVAP readiness not set
Common causes of P0457
- Most likelyFuel cap not closed, not clicked in or forgotten
- PossibleFuel cap seal faulty or non-original cap
- PossibleFiller neck sealing surface damaged or capless flap sticking
- Less likelyVent valve stuck open
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Fuel capFuel filler neckEVAP system
What each part of P0457 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 4 | Area: auxiliary emission controls (catalytic converter, EGR, EVAP). |
| 57 | The exact fault in that area. |
What to do next
- Note P0457 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0457
What does P0457 mean?
P0457 means "EVAP System Leak Detected (fuel cap loose/off)". The evaporative emission (EVAP) system stores fuel vapour from the tank in a charcoal canister; a purge valve lets the engine draw it off, and a vent valve opens the canister to fresh air. It is a generic code, so it means the same on every make.
Is it safe to drive with P0457?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P0457 fail an emissions test?
Yes, it can. P0457 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0457 to fix?
Difficulty: easy. A typical repair takes 0 to 0.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P0457 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.