Trouble codes › P0457
P0457 Evaporative Emission System Leak Detected (Fuel Cap Loose/Off)
EVAP
P0457 means the gas cap is loose, off or not sealing.
The EVAP system's self-test found a large leak right after a refill, which the engine computer takes as a gas cap left loose or off.
Safe to drive. Tighten or replace the cap; the light usually goes off after a few days of driving.
Common causes
- A gas cap not tightened, left off or cross-threaded
- A worn cap seal or the wrong cap
- A damaged filler neck seal (capless systems: a dirty or stuck flap)
Symptoms
- Check-engine light or a "check fuel cap" message
- Fuel smell sometimes
Common on: Honda Civic
What to check first
- Tighten the cap until it clicks; check its seal for cracks.
- On capless filler necks, check the flap closes fully and isn't dirty.
- Clear the code or drive a few days; the light should go off on its own.
- If it returns, replace the cap with one made for your vehicle and check for a large EVAP leak.
What does P0457 mean on your vehicle?
The likely cause depends on your engine. iRepair researches your exact year, make, model and engine (service bulletins, recalls and owner reports) and tells you what to check first. Your first 3 questions are free.
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Related codes
General guidance for P0457 on most vehicles. Some makers use the same code a little differently; confirm in the service information for your vehicle, put safety first, and see a professional when in doubt.