You go to the counter at Autozone or Advance Auto and tell them you have the Check Engine Light on and ask them to scan it for you (it is a free service). After they scan it, make sure you get the code from them (and post it here). They might just tell you what to do to get rid of the code (usually buy some part from them) but get the code and post it here. They will probably erase the code too after that. If they don't, we can show you how to later. But for now, go get it scanned (unless yours is a 1995, then there is a way to scan it with a paper clip). So what year is your car?