1999 jeep Cherokee classic. It will not go into 1st gear. It says it is the input speed sensor. Check gauge light comes on now. I replaced the alternator , input speed sensor and battery. Its over c

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 bad

it can NOT shift, one such sensor is SPEED. MPH or VSS

the tail shaft all all 42RE transmission has a tail rpm sensor

when dead the cars speedometer goes dead, and the TCM

is 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 RPM

there are 3 RPM sensor

Engine, RPM called, CKP

tranny input sensor that tells the TCM true clutch slip at all time

and 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 sensor

P-0715 is a bad input sensor

P0720 and up are output sensor errors.

the 500 , is the 3rd sensor, the tail shaft sensor that runs the speedo

1st google hit.

http://www.jeepsunlimited.com/forums/showthread.php?548105-P0500-Vehicle-Speed-Sensor-Malfunction



next time post real DTCs

so we can jump on the exact part and the simple tests





the beauty of 3 sensors, is the transmission runs better

shifts better

and the OBD2 diagnostics are dead nuts, accurate.

it can see illegal gear slips (bad clutch packs) in any gear

and tell you. one of the best there.are

if you had new car, with 9speed, good luck keeping that card house going.. really.