Did you try replacing the gas cap? Mine just started leaking a few months back and threw the DIC message. The original looked okay, but it wouldn't seal. That'* only a 10 dollar solution if it works. I suggest that if you are still getting the Check gas cap on the DIC, to start there.
I find myself replacing the emissions vacuum fittings about once a year. The tee on the fuel regulator, and the reducer where the other end attaches to the */C vent valve also cracks,