OBD-II code guide

P0457 EVAP Leak Detected Fuel Cap Loose or Off

P0457 usually means the EVAP system detected a leak that may be related to the fuel cap area.

What it means

The system could not hold vapor pressure and the leak may be large enough to suggest a loose cap or cap seal issue.

Common symptoms

  • Check engine light after fueling
  • Fuel smell near cap
  • Usually normal driving
  • Emissions readiness issue
  • Possible repeated EVAP codes

Likely causes

  • Loose fuel cap
  • Damaged cap seal
  • Filler neck issue
  • EVAP hose leak
  • Vent or purge valve issue

First checks

  • Tighten the cap if equipped.
  • Inspect cap seal and filler neck.
  • Do not top off after the pump clicks.
  • Record related EVAP codes.