OBD-II code · Powertrain (generic)
P0455 Evaporative Emission System Leak Detected (Large Leak)
A large leak has been detected during the EVAP system pressure or vacuum test — large enough that the system cannot hold pressure for the diagnostic interval. Typically a missing fuel cap, disconnected hose, or split canister.
Is it safe to drive with P0455?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyFuel cap missing or not seated
- Most likelyEVAP hose disconnected
- PossibleCharcoal canister cracked
Symptoms
- Check engine light on
- Possible smell of fuel near tank or engine bay
- Failed emissions inspection
- Loose-cap warning may appear
Repair at a glance
- Difficulty
- Easy
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.1–2.5 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Fuel Filler Cap, Evap Canister, Evap Hose
Related codes
- P0452Evaporative Emission System Pressure Sensor Low Input
- P0453Evaporative Emission System Pressure Sensor High Input
- P0454EVAP System Pressure Sensor/Switch A Circuit Intermittent
- P0456Evaporative Emission System Leak Detected (Very Small Leak)
- P0457Evaporative Emission System Leak Detected (Fuel Cap Loose/Off)
- P0458EVAP System Purge Control Valve A Circuit Low
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.