I have a 2006 Grand Cherokee Limited with a 5.7 liter Hemi. It had a leak in the charcoal canister that was causing my check engine light to come on, and a message telling me to check my gas cap. I had the evap system fixed, and the check engine light is off. It still has the message "Check gas cap" on the information center. Did my mechanic miss something? Is the gas cap actually bad? Any ideas where else to look for this problem?