New to the site. Hope you folks can help.

My check engine light just came on my 1990 300ce. Bout a week ago, it began starting but not staying on and this would happen about two times every so often. It runs smooth. I think it may be the gas line, but not sure. How do I find out where the check engine code is? I already have a list of what the codes mean just don't know how to get it off the car.

Thanks
Chef