The computer flashed code 55 which means that there are no codes in your ECM. You can try disconnecting the positive battery terminal for about 30 sec to 1 min and reconnect. If you buy a haynes manual from any auto parts store, it list the engines codes that are most common in the emission section. The book is around $10-13 and well worth it. I do all of my own self diagnosis instead of going to a shop.
1997 Black XJ Sport 4x4, 1" Shackle/coil spacer lift, Ram Brush guard w/ 6in spot lights, Smittybilt Nerf bars, Class III Hidden Hitch, Elliptical Driving Lamps, Prime Wheels#234 15x8.5, 30x9.50r15, BFG AT's, JVC CD player, Alpine V12 Amp, 1-12in RockfordFosgate Subs, 5-1/4 Rockford Fosgate component speakers in doors & sound bar, Euro-spoiler, Pacesetter Cat-Back, Optima Red Top battery, HID Headlamp Conversion, Gabriel Hijacker Air Shocks on rear axle