My 2003 Elantra has 48,000 miles on it and is running fine. I had the check engine light checked at the auto parts store and was told the code is 455. Any ideas what this is?

 

P0455 =Evaporative Emission Control System Leak Detected (no purge flow or large leak)

This indicates a fuel vapor leak or lack of purge flow in the EVAP control system. It means a large leak has been detected. The (EVAP) emission control system prevents the escape of fuel vapors from a vehicle's fuel system. Fuel vapors are routed by hoses to a charcoal canister for storage. Later, when the engine is running a purge control valve opens allowing intake vacuum to siphon the fuel vapors into the engine.

AP0455 most likely means one or more of the following has happened:
- A loosegas cap
- A non-conforming gas cap (i.e. not factory/original brand)
- Other leak or damaged piece in EVAP system

The most common repair is to:
- Remove and reinstall the gas cap, clear the codes, and drive for a day and see if the codes come back.
- Otherwise, replace the gas cap, and/or
- Inspect the EVAP system for cuts/holes in tubes/hoses (you may hear a vacuum noise or smell fuel), repair if necessary

 

Thank you very much for the detailed reply. The gas cap is the original; I may try replacing it if the light returns. (No apparent leaks.)

 

First, make sure the cap is tight. It must click at least 3 times when tightening it.

 

Ive had trouble getting an inspection done on my vehicle due to my EVAP system with a code P0455. I have taken it to several places which in all cases it wasnt my gas cap or hoses; a smoke test was done and not detection of leaks there. Could this possibly be my vent valve or Canister? If so id like to know just to save me the time and money on spend more for diagnostic testing. Thanks!