P0455 Evaporative Emission System Leak Detected (Large Leak)
The system that traps fuel vapour from the tank has found a large leak.
Common causes
- Loose, missing or damaged gas cap
- Cracked or disconnected EVAP hose
- Faulty purge or vent valve
- Leaking filler neck
Symptoms
- Usually none besides the check engine light
- Sometimes a fuel smell
Can I drive with it?
Safe to drive – this is an emissions fault, not a performance one. Fix it before your next emissions test.
Tip: Start with the gas cap: tighten it until it clicks, or replace it if the seal is cracked. The code may take a few days of driving to clear on its own.
Which scanner reads it?
Any OBD2 scanner reads it. Some better tools can run an EVAP leak test on supported cars.
Budget tools like the ANCEL AD310 read it; tools with live data and graphing – like the BlueDriver or OBDLink MX+ – help you find the cause. Not sure which fits you? Try the Find My Scanner quiz.
In the data
How common is it? At New York’s emissions inspections in 2020–21, P0455 was the #3 code found on cars that failed – 4.1% of all the codes found.
Of the vehicle complaints owners filed with NHTSA from 2015 to 2025, 44 quote P0455 – most often from Chevrolet, Hyundai, Ford owners. Complaints lean toward serious problems, so treat this as a sign of how often the code turns up in real reports, not how often cars get it.
Both sources are compared on the Trends page.
Related codes
General information to help you understand a code – not a diagnosis. Your car’s service information or a qualified mechanic has the final word. See how we research.