Chrysler Repair: 2004-pacifica, gas cap, trouble code

Question
main computer is transmitting trouble code po456-small evap leak detected.I first checked the gas cap which was on tight.The service engine light remains lit all the time.Visually checked the hoses under hood which appear to be ok.The engine runs normally.Any technical expertise as to what component would cause this code to turn on and how to repair?
                                thanks
                                bob n

Answer
a gas cap would be a med or large evap leak. The leak u are looking for is .0020 in size  thats the size of a pin head.
Look for cracks in hoses around where they meet other hoses or go into something  thats where they like to leak the most. When  and if u do find one  don't unplug your batt  just leave the light on. If u fixed it  the computer will turn it off in a few days when it runs the same test that it failed the first time.  U might have more then one leak though.