AC stops working when CEL come on

I have a 2008 Cobalt LS 2.2L. My mechanic recently made a repair to the emissions system and ever since, the AC stops working when the Check Engine Light comes on. I noticed that when I clear the code, the AC works. My neighbor let me use his cheapo scanner and it found a 7e8 code. I googled it and it says it could be a multitude of things. Anyone have any ideas? Thanks!!