evaporation leak on 2002 Chevrolet Blazer

what constitute an evap.leak,and where to find this leak?

Asked by for the 2002 Chevrolet Blazer
This is a pretty large subject. Here is an article I wrote about for 1 of the more common Evaporative System Codes and there are several. You could start with a new gas cap from the dealer, as Chevy gas caps tend to leak after awhile.