P0457 EVAP system leak detected (fuel cap loose/off)
What P0457 means
The engine control unit detected a sudden large leak in the fuel vapour system, typically right after refuelling, which matches a fuel cap that is loose, missing or not sealing.
P0457 is a generic SAE J2012 code: it means the same on every make. The exact cause still depends on the car, so read the freeze-frame data before replacing parts.
At a glance
- Severity
- Low
- Typical repair cost
- 5–60 €
- Workshop time
- 0–0.5 h
- Repair difficulty
- Easy
- DIY possible
- Yes
- Check engine light
- Yes
- Affects emissions test
- Yes
Parts and labour at an independent workshop in Europe. Main dealers charge more; the cause decides the bill, not the code.
Symptoms
- Check engine light or fuel cap warning on after refuelling
- Possible fuel smell
- No change in how the car drives
Common causes
- Fuel cap not tightened or left off
- Worn or damaged fuel cap seal
- Wrong or non-original fuel cap
- Damaged filler neck sealing surface
Can I keep driving with P0457?
This is a low-priority fault. Tighten the fuel cap until it clicks and keep driving; the light should go out on its own after a few drive cycles.
What to check first
- Remove the fuel cap, check the seal, and refit it until it clicks
- Clear the code or let it clear after several drive cycles
- Replace the cap if the seal is cracked or the code returns
- Inspect the filler neck for damage if a new cap does not help
Related codes
- P0456 EVAP system very small leak detected
- P0455 EVAP system large leak detected
- P0453 EVAP pressure sensor/switch A circuit high
- P0452 EVAP pressure sensor/switch A circuit low
- P0451 EVAP pressure sensor/switch A range/performance
- P0461 Fuel level sensor A circuit range/performance
- P0462 Fuel level sensor A circuit low
- P0463 Fuel level sensor A circuit high
Data: TORKO fault-code catalogue, built on OBDex (CC0-1.0) and reviewed against workshop practice. Informational only — it does not replace a diagnosis by a mechanic.
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