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)

  1. Loose or missing gas cap (literally just tighten until it clicks)
  2. Failed gas cap seal (cheap replacement)
  3. 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

P0440P0442P0455P0456

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