Evap control System

My service engine soon light came on and I had it diagnosed and evap control system was the code. The guy told me to try the gas cap so I did and he reset it, but the code came back up. I don't know where to go from here. Does anybody else know what my next steps should be? I'd appreciate the help.

My service engine soon light came on and I had it diagnosed and evap control system was the code. The guy told me to try the gas cap so I did and he reset it, but the code came back up. I don't know where to go from here. Does anybody else know what my next steps should be? I'd appreciate the help.
There are several codes that relate to the EVAP system. Some are for leaks and others are for electrical or performance concerns.
If "The guy" diagnosed your vehicle correctly, he wouldn't have told you to "try the gas cap".
What specific code do you have?
Did "the guy" perform a EVAP flow and leak test?

There is a leak in the evap system somewhere.Only way to find the evap leak is a smoke machine using with GM's factory scan tool,Tech 2 or a Vetronix scan tool.A Snap On scanner or OTC scan tool will not work with the smoke machine.Where did you get the codes read?If it was AutoZone,stay away AutoZone and they are 99.9% wrong.My father can prove they are wrong.

The guy was a mechanic that told me about the gas cap. The second time i had it diagnosed, the guy who read it was a formal co-worker that mechanics on the side and he had one of those machines. I'm not really sure what exactly the code read, just that its evap control. I guess I can find that out before I make myself look anymore like a dumbass. I agree, autozone sucks. I hate that store and never go to it.

I got a "service engine light" on when my gas cap was loose and it also said "tighten gas cap" in the DIC. I tightened it and the light went off.