P0457: EVAP System Leak Detected (Fuel Cap Loose/Off)
Severity: low
What it means: The evaporative emissions system, which traps fuel vapor from the tank, found a leak (fuel cap loose or off) leak during its self-test.
Safe to drive? Yes, it's generally safe to drive. It's an emissions issue, though it will fail an inspection.
Common symptoms
- Check-engine light
- Sometimes a faint fuel smell
- Usually no drivability change
Likely causes, ranked
- Loose, damaged or wrong gas cap$0–$28DIY
CarMD 2024: free to tighten, about $28 average to replace
- Cracked EVAP hose or sealShop
- Leaking purge or vent valve$144Shop
CarMD 2024 national average about $144
- Leaking charcoal canister or filler neckShop
What it means: The evaporative emissions system, which traps fuel vapor from the tank, found a leak (fuel cap loose or off) leak during its self-test.
Severity: Low. Safe to drive? Yes, it's generally safe to drive. It's an emissions issue, though it will fail an inspection.
DIY or shop?
Check and tighten or replace the gas cap first. A smoke test at a shop finds the rest.
Before you replace parts
- Read all stored codes and freeze-frame data. Fix misfire, fuel or sensor codes before chasing emissions codes.
- Check the simple things first: connectors, vacuum hoses, fluid levels and the gas cap.
- Clear the code only after a repair, then confirm it stays off after a few drives.
- Check your VIN for recalls and service bulletins.
Safety / mechanic note
Generally not urgent, but a code only points to a system, not always a specific part. Verify with a mechanic before buying expensive parts.