Check Engine Light

I have 1998 GMC Sonoma 2.2L. I put a new battery in last night and after I started the truck with new battery and now the check engine light is on I have noticed that my alternator seems to make noise before and after the new battery was installed could this be it?

I have 1998 GMC Sonoma 2.2L. I put a new battery in last night and after I started the truck with new battery and now the check engine light is on I have noticed that my alternator seems to make noise before and after the new battery was installed could this be it?
It sounds posible that it could be your alternator. Wouldn't hurt getting it checked out at a near by auto parts store. Sounds strange it just came on after put the new battery in....