EVAP large leak detected
What P0455 means
Your car's computer set P0455: EVAP large leak detected. It belongs to the emission controls group of codes. It is a generic code, so it means the same thing on every make. The check engine light usually comes on once the fault has been seen on two drives in a row. Until then it shows up as a pending code.
Can I keep driving? Usually safe to drive. The car may run normally, but it will not pass an emissions test until this is fixed.
Common causes
- Loose or worn gas cap
- Leaking EVAP hose or valve
- Failed fuel tank pressure sensor
Fix the cheapest, most likely cause first. Clearing the code without a repair only turns the light off until the fault comes back.
Check it yourself
Start with the gas cap. Then read the EVAP readiness monitor on the Car tab.
Torque Deck reads P0455 with a cheap Bluetooth OBD2 adapter. It also shows the freeze frame (engine conditions at the moment the code set) and the live data you need to narrow it down.
Parts
Parts most often replaced for P0455: gas cap. Confirm the cause first, and match the part to your exact engine.
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Related codes
This page explains what the code usually means. It is not a diagnosis of your car. When in doubt, ask a mechanic.