P0455
Evaporative Emission System Leak Detected (large leak)
- Severity
- Low
- Driving
- No driving restriction
A large leak was detected in the evaporative emissions system - the sealed circuit that captures fuel vapour from the tank so it can be burnt by the engine rather than escaping. This code does not affect how the car runs. It matters for emissions compliance, and it will fail a test.
Possible causes
- CommonLoose, damaged or incorrect fuel filler cap
- CommonCracked or perished EVAP hose
- PossibleFaulty purge valve stuck partly open
- PossibleFaulty vent valve not sealing
- PossibleCracked charcoal canister
- RareLeaking seal on the fuel pump or level sender in the tank
What you might notice
- Check engine light on, with no change in how the car drives
- Sometimes a faint fuel vapour smell
- Failed emissions test
What to check, in order
- Start with the fuel cap - remove it, check the seal, refit until it clicks, clear the code and drive for a few days.
- Inspect the EVAP hoses you can reach for cracks and perished rubber, particularly where they pass near hot components.
- Check the charcoal canister for cracks, especially on vehicles where it sits low and exposed at the rear.
- A smoke test is the reliable way to find these leaks and is what a workshop will do. Chasing a small EVAP leak by eye is often wasted effort.
- The very small leak variant of this code is the hardest to find by inspection - go to a smoke test sooner rather than later.
Read this code from your own car
Plug an ELM327 adapter into the OBD-II port under the dashboard. Pin16 reads every stored, pending and permanent code, explains each one like this page does — offline, with no account — and shows what the car recorded when the fault was set.
Where this code sits
P00xxP01xxP02xxP03xxP04xxP05xxP06xxP07xxP08xxP09xxP0AxxP0BxxP0CxxP0DxxP0ExxP0FxxP10xxP11xxP12xxP13xxP14xxP15xxP16xxP17xxP18xxP19xxP1AxxP1BxxP1CxxP1DxxP1ExxP1FxxP20xxP21xxP22xxP23xxP24xxP25xxP26xxP27xxP28xxP29xxP2AxxP2BxxP2CxxP2DxxP2ExxP2FxxP30xxP31xxP32xxP33xxP34xxP35xxP36xxP37xxP38xxP39xxP3AxxP3BxxP3CxxP3DxxP3ExxP3Fxx
Auxiliary emission controls
P0400P0401P0402P0403P0404P0405P0406P0407P0408P0409P0410P0411P0412P0413P0414P0415P0416P0417P0418P0419P0420P0421P0422P0423P0424P0425P0426P0427P0428P0429P0430P0431P0432P0433P0434P0435P0436P0437P0438P0439P0440P0441P0442P0443P0444P0445P0446P0447P0448P0449P0450P0451P0452P0453P0454P0455P0456P0457P0458P0459P0460P0461P0462P0463P0464P0465P0466P0467P0468P0469P0470P0471P0472P0473P0474P0475P0476P0477P0478P0479P0480P0481P0482P0483P0484P0485P0486P0487P0488P0489P0490P0491P0492P0493P0494P0495P0496P0497P0498P0499