You will need an OBD II code reader to get the codes out. It will plug into the 16 pin connecter under the dash on the drivers side.
Try
www.scantool.net for some cheaper alternatives. I just bought on for my 97 and spent $200 CDN on it. However it works awsome and will do anything 95 and above. any make.
Here is the one I bought
http://www.troublecodes.net/articles...e_reader.shtml
at least this will give you an idea what you are in for