Trouble code
P0455
Evaporative Emission System Leak Detected (Large Leak)
What P0455 means
The fuel vapor containment system is leaking badly enough that it cannot hold pressure. Fuel vapor is escaping to atmosphere.
Symptoms you may notice
- Check engine light only
- Sometimes a fuel smell
- Failed emissions test
Common causes, cheapest first
- Loose, cracked or wrong fuel cap
- Cracked EVAP hose
- Failed purge or vent valve
- Damaged filler neck
- Leaking charcoal canister
Before you buy anythingCheck the fuel cap first, every time. Tighten it until it clicks, drive for a few days, and see whether the light clears itself. It is free and it is the cause more often than any other.
What to do next
- Confirm the code with your own scan tool, or have it read free at a chain parts store.
- Decode your VIN so you know your exact engine and build date.
- Work down the causes above from cheapest to most expensive.
- Search NHTSA for a recall or service bulletin covering this symptom on your vehicle.
- Read the engine buying guide before ordering.
P0455 is a generic OBD-II code, standardized across every make and model sold in the US from 1996 onward. The meaning is the same on any vehicle; the specific part and its location are not.
Parts
Parts commonly needed for P0455
These go to Amazon. We earn a commission if you buy, at no extra cost to you — see our affiliate disclosure. Which one you actually need depends on diagnosis — read the note above first.
Confirm fitment against your VIN on the listing page before ordering. A part that matches your year and model can still be wrong for your build date or engine code.