Check Engine Code
P0457
EVAP System Leak Detected (Fuel Cap Loose / Off)
Severity: low
DIY difficulty: 1/5
Typical cost: $0–$50
What P0457 means
Some vehicles set this code specifically when the EVAP self-test fails in the pattern that suggests the gas cap is loose or off — basically the ECM telling you 'check the gas cap.'
Symptoms
- Check engine light
- "Check gas cap" message on some vehicles
Likely causes (most common first)
- Loose or missing gas cap (literally just tighten until it clicks)
- Failed gas cap seal (cheap replacement)
- Damaged filler neck
Can I keep driving?
Low — mostly emissions/economy
Typical repair cost
DIY fixes can start near $0 (parts only). Shop repairs for P0457 typically run up to $50 depending on the underlying cause and vehicle. Start with the most common cause — Loose or missing gas cap (literally just tighten until it clicks) — before throwing parts at it.
Related codes
Confirm P0457 yourself in 60 seconds
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