yo my check engine light has been on basically since i bought my 98 cherokee. its probably just a O2 sensor. how many miles are on it and whens the last time you changed your sensors?
and ill agree with the previous post, drive it to autozone or something, and have them read the code. i wouldnt worry about your jeep stranding you, that only happens when your off road haha.
gimme some more info and ill be able to help you out, if not join www.naxja.org
they will have all the answers you need to fix your xj the right way, and pretty cheap too.
also, im jealous that you had your jeep in moab, hopefully i can make it to the easter jeep safari there this year, pretty pumped.