Is it the '99 that's in your signature? If so, it's an OBD2 vehicle and yes you can do that. I'm not sure exactly what type of connection you would have on a WJ. But, yes you can get programs that you can use on your laptop and then hook up to your diagnostic port. those programs are several thousand dollars though. You can also use a scan tool...but they are also several thousand for anything of descent quality. The scan tools that can change all that stuff are usually up around $20,000.
So if you can find someone that already has one...that's the way to go.