Gass Cap I have had my engine light reset. The light is on again as soon as I fill up with gas. How do I fix it?

Disconnect the negative battery cable for 30 minutes. Reconnect after and the code will clear. However if the problem persists, the code will come back with in 20 miles or 30 minutes.

When last did you service the vehicle ?
did they use the proper fuel ?

Chances are the service time is near where you will need to do a basic service, Plug , plug wires, filters etc. And reset the counter.
the fuel ting is just a coincidence.

You set a evaporative code by leaving the gas cap off..Put the cap back on ,as long as your fuel level is between a 1/4 to 3/4 the vehicle will eventually do another test and the light will go out

the cap most likely set an evap code in the computer have it checked with a scan tool.if the cap is on tight then just clear the code and the light will go out.

Check engine light might have came on because of loose gas tank cap, but it's a good idea to read the code and check if it's not something else, you can take your car to an Auto Zone and they read the code for free and tell you the cause also. But if you want to reset the check engine light, only way is to disconnect the battery terminals and let it set overnight, check engine light will be reset. Hope it helps and let me know if you need more advice. Please don't forget to rate the answer it helps with my ratings, thanks!

code p 0440 refers to the EVAP system --purge valve malfunction
check wiring and replace the purge valve

No the flap inside the fuel filler pipe is just an anti theft device to make it more difficult to siphon fuel out of the tank. The most likely cause for the code it the fuel cap itself. If you don't get the gas cap tight after you fuel up, it can set a computer code and turn on the Check Engine Light. After you check to make sure the cap is on tight, clear the engine code and see if it comes back on. If it does then have the fuel cap tested to make sure that it doesn't have a vaccuum leak.

you have to understand that there is a leak in the system other than the gas cap for the evaporative system. The system needs to be professionally closed, and smoke introduced into to find the leak, and a through component check, eg.. purge valve vapor canister vent solenoid all functioning correctly

if it truly set code for "loose fuel cap" or po455 large leak, then tightening the cap and driving a couple days should reset on its own. if not then get it checked for free at autozone and report back with code # and can help from there. they'll ck for free but are not allowed to reset.

on 2005 mitsubishi endeavor . srs is on . how do you turn it off or reset it