OBD-II code guide
P0455 Large EVAP System Leak Detected
P0455 means the evaporative emissions system cannot hold pressure or vacuum during a leak test.
What it means
Fuel vapor containment has a large leak, often from a cap, hose, valve, or canister issue.
Common symptoms
- Steady check engine light
- Fuel smell near vehicle
- Hard starting after fueling in some cases
- No obvious drivability issue
Likely causes
- Loose or damaged fuel cap
- Cracked EVAP hose
- Stuck purge valve
- Damaged charcoal canister
- Vent valve fault
First checks
- Inspect fuel cap seal.
- Confirm the cap clicks tight.
- Look for cracked vapor hoses if accessible.
- Note if symptoms started after refueling.