check enigine light

Vehicle Information: Year: 2001; Engine (Size, Modifications): 3.6; Total Mileage: 12050;

my check engine light went on after i had my car serviced. the service included change oil and filter, 2 year brake service-changed brake fluid and the yearly nys inspection.upon driving home from the shop, my spoiler light came out. when i got home and left the hopuse after 1 hour the spoiler light was no longer on but the check engine light came on. the gas cap is tight, i fulled up 24hrs ago. i read ur response regarding heat cycles. im aware the quickest way is to bring it to dealer and have codes read, which i will do but from now until they can schedule me for service, weat else can i do. What did you mean by heat cycles, 20 to 100 might clear the light.thanksadve