P0455 EVAP system large leak detected
What P0455 means
During its self-test the engine control unit sealed the evaporative emission (EVAP) system and could not hold vacuum, which indicates a large opening. Fuel vapour can escape into the air.
P0455 is a generic SAE J2012 code: it means the same on every make. The exact cause still depends on the car, so read the freeze-frame data before replacing parts.
At a glance
- Severity
- Low
- Typical repair cost
- 20–350 €
- Workshop time
- 0.1–2.5 h
- Repair difficulty
- Easy
- DIY possible
- Yes
- Check engine light
- Yes
- Affects emissions test
- Yes
Parts and labour at an independent workshop in Europe. Main dealers charge more; the cause decides the bill, not the code.
Symptoms
- Check engine light on
- Possible fuel smell around the car
- No change in how the car drives
Common causes
- Loose, missing or wrong fuel cap
- Disconnected or split EVAP hose
- Purge valve or vent valve stuck open
- Cracked charcoal canister or filler neck
Can I keep driving with P0455?
This is a low-priority fault. Check the fuel cap first; you can keep driving, and if the light returns, have the system smoke-tested.
What to check first
- Check the fuel cap is present, correct and tightened until it clicks
- Inspect visible EVAP hoses at the engine and near the tank for disconnections or cracks
- Check the purge and vent valves for sticking
- Have a smoke test done to find the leak if it is not obvious
Related codes
- P0456 EVAP system very small leak detected
- P0453 EVAP pressure sensor/switch A circuit high
- P0457 EVAP system leak detected (fuel cap loose/off)
- P0452 EVAP pressure sensor/switch A circuit low
- P0451 EVAP pressure sensor/switch A range/performance
- P0449 EVAP vent valve control circuit/open
- P0461 Fuel level sensor A circuit range/performance
- P0462 Fuel level sensor A circuit low
Data: TORKO fault-code catalogue, built on OBDex (CC0-1.0) and reviewed against workshop practice. Informational only — it does not replace a diagnosis by a mechanic.
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