All codes
P0455Emissions System
EVAP System Large Leak Detected
Diagnose P0455 large EVAP leak code. Find out what causes large evaporative system leaks and how to repair.
What you may notice
Symptoms
- 01Check engine light on
- 02Strong fuel odor possible
- 03No drivability symptoms typically
- 04Failed emissions test
Where to look first
Common causes
- 01Missing or very loose gas cap
- 02Disconnected EVAP hose
- 03Cracked charcoal canister
- 04Stuck open purge or vent valve
- 05Major fuel system leak
Step by step
What to check and repair
- 01Verify gas cap is present and tight
- 02Replace gas cap if needed
- 03Visually inspect EVAP hoses
- 04Check charcoal canister
- 05Test purge and vent valves
What Does P0455 Mean?
P0455 indicates a large leak in the EVAP system - larger than what P0442 detects. This usually means something is significantly wrong or disconnected.
Easier to Find
Unlike small leaks, large EVAP leaks are usually easier to locate because the problem is more obvious - often a disconnected hose or missing cap.
Start Simple
Check the gas cap first. A missing or very loose cap will trigger this code immediately.