I am getting a message saying the following: tighten fuel filler cap but my cap is tight. Does anyone have a remedy and explanation. Thanks.

 

It will come on when the vehicle runs the EVAP monitor and it detects a leak. Just make sure that you tighten 1-3 clicks (whatever is written on the cap). It may take several days or weeks to clear on it's own. The PCM has certain criteria to be met before the monitor is run so it does not actually check every key cycle or run session. Once the monitor runs again and the gas cap is indeed not tight or it detects a leak, the CEL should come on. It is possible that the cap could actually be bad and not sealing sufficiently which should eventually cause the CEL to come on.

 

The Interwebz is chocked full of experiences like yours with their Honda. Make sure you get three clicks every time you put the cap on. Like sOLLEx said, it may take a bit of driving to reset.

 

Thanks very much. I really appreciate it.