P0457 minor

Evaporative Emission Control System Leak Detected (Fuel Cap Loose/Off)

What does P0457 mean?

The P0457 code means the vehicle's onboard diagnostic system has detected: Evaporative Emission Control System Leak Detected (Fuel Cap Loose/Off). This is a minor severity code.

Common Symptoms

  • Check Engine Light on
  • Fuel smell near vehicle
  • No drivability issues

Probable Causes (Ranked by Likelihood)

  • Gas cap not fully tightened Very High
  • Missing gas cap High
  • Damaged gas cap seal High

Step-by-Step Diagnostic Procedure

  1. Remove and re-install the gas cap, tightening until it clicks.

  2. Inspect the gas cap O-ring seal for cracks, tears, or compression set.

  3. Clear the code and perform two full drive cycles. If the code does not return, the gas cap was the issue.

  4. If the code returns after replacing the gas cap, proceed with a full EVAP smoke test.

Frequently Asked Questions

Will P0457 go away on its own after tightening the gas cap?

The Check Engine Light will not go off on its own immediately. The EVAP monitor must run and pass two drive cycles. You can clear the code manually with a scan tool for immediate results.

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