It says ? what says? the SCAN TOOL>?non GRAND, (no engine stated, so fail there 1st)my guess is you have a DTC and forgot to post that. why do that?the DTC is covered in the FSM manual, and shows what is failing.why not read the FSM and do what it says to do?ill no attempt to read the FSM for you,. and that vague error.why not log in to alldata.com and stop guessing. at parts.there is no reason to gue$$my guess at he DTC,P0500"or was it the P07xx series, all A/T errors.P1xxx codes are factory code, got them? need all codes, not just 1 of many. and using a real scan tool not some POS autozoned junk (free)p0500 is ASE jargon (best ) is VSS sensors. vehicle speed sensor.the transmission TCM monitors many inputs, and if they are badit can NOT shift, one such sensor is SPEED. MPH or VSSthe tail shaft all all 42RE transmission has a tail rpm sensorwhen dead the cars speedometer goes dead, and the TCMis at a lost to shift to 2nd gear, if speed is 0 all day.a hopeless deal there.if the battery voltage is not over 15v, its not overcharging, running.99 is a nice jeep, id fix mine, ive had many.the tranny has 2 speed sensors.the front sensor does not do MPH, its just engine tranny input RPMthere are 3 RPM sensorEngine, RPM called, CKPtranny input sensor that tells the TCM true clutch slip at all timeand if the TCC works or not.the tail shaft is the true speed sensor, vehicle speed, it\'s on tail shaft.my guess, is the tail sensor is bad and you replaced the front sensorP-0715 is a bad input sensorP0720 and up are output sensor errors.the 500 , is the 3rd sensor, the tail shaft sensor that runs the speedo1st google hit.
http://www.jeepsunlimited.com/forums/showthread.php?548105-P0500-Vehicle-Speed-Sensor-Malfunctionnext time post real DTCsso we can jump on the exact part and the simple teststhe beauty of 3 sensors, is the transmission runs bettershifts betterand the OBD2 diagnostics are dead nuts, accurate.it can see illegal gear slips (bad clutch packs) in any gearand tell you. one of the best there.areif you had new car, with 9speed, good luck keeping that card house going.. really.