OBD-II diagnostic trouble code
P0455Safe to drive
Evaporative Emission System Leak Detected (Large Leak)
The EVAP system captures fuel vapor from the tank so it doesn't escape into the air, and periodically the computer runs a pressure test on it. This code means the system detected a leak large enough to fail that test — most often something as simple as a loose or missing fuel cap.
Symptoms
- Usually no drivability symptoms at all
- Sometimes a faint fuel smell near the fuel filler area
- Check engine light on, possibly clearing itself after a few drive cycles if the cause was a loose cap that's since been tightened
Likely causes
- Fuel cap loose, missing, or with a worn seal — the single most common cause by far
- A cracked or disconnected EVAP hose somewhere between the tank and the charcoal canister
- A failed purge or vent valve stuck open
- A cracked charcoal canister or a corroded fuel tank sending unit gasket
How to diagnose it
- Check and reseat the fuel cap first — tighten until it clicks, then clear the code and see if it returns after a few drive cycles
- Visually inspect all visible EVAP hoses (often running along the top of the fuel tank) for cracks or disconnection
- A smoke test at a workshop is the most reliable way to pinpoint a leak that isn't visible or obvious
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Code names are compiled from open/standardized SAE and ISO references. Explanations, symptoms, causes and fixes are original. Covers generic (P0/C0/B0/U0) codes only — manufacturer-specific codes are planned for a future update.
Frequently asked questions
Can I drive with P0455?
In most cases, yes — P0455 is generally not an urgent safety issue and the car is usually safe to drive for a while. Still, get it checked soon, since the underlying cause can affect fuel economy or emissions the longer it's left.
How much does it cost to fix P0455?
Typical repair costs for {code} range from roughly 15 to 350 EUR, depending on the specific cause and your car — see the fixes listed above for a breakdown.
What causes P0455?
Fuel cap loose, missing, or with a worn seal — the single most common cause by far A cracked or disconnected EVAP hose somewhere between the tank and the charcoal canister A failed purge or vent valve stuck open
Reviewed by Artyom SemenovAutomotive Editor · Fact-checked by Yauheni Kapliarchuk, Editor-in-Chief