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P0455: Evaporative Emission System Leak Detected (Large Leak)

Severity: Low Usually safe to keep driving, but get it checked.

What does P0455 mean?

The EVAP self-test found a large leak, or no vapor flow. A missing or loose gas cap is a very common cause.

Generic OBD-II definition: Evaporative Emission System Leak Detected (Large Leak). Confirm applicability in your vehicle service information.

Common causes

  • Loose, damaged, or wrong gas cap
  • Cracked EVAP hose
  • Leaking purge or vent valve
  • Damaged charcoal canister
  • Leaking filler neck

Symptoms

  • Usually no drivability symptoms
  • Possible faint fuel smell
  • Will likely fail an emissions inspection
  • Possible fuel smell

Can I keep driving with P0455?

Severity: Low Usually safe to keep driving, but get it checked.

If the check engine light is flashing or the car runs badly, stop driving and have it checked.

Typical fixes

  • Tighten or replace the gas cap first, then clear the code and drive a few days
  • Have a smoke test done to locate leaks
  • Test purge and vent valves

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