You forgot to say CEL is stuck on driving, or OD flashes?
short answer. VSS (veh, speed sensors, there are 2)
car has 2 vss,
the ECU and TCM can use either, both ECU and TCM when scanned tell you , when either are bad, (CEL glows, od lashes , scans told you this)
is the odometer dead too? if it dies the VSS1 in the head dies with it, and is most times a bad speed cable if both die (needle dead and odometer dead)
snapped cable cause 3 failures, VSS/needle mph/odometer. (can be the end of cable , clip broken , and is common)
if only the needle is dead, only, then the other 2 do work ok. see, the needle is magnetically driven, and can JAM and not effect the other parts that are pure raw mechanical drive.
easy no?> there are 3 things running off 1 cable, so monitoring all 3 , tells you what's up.
the TCM will use VSS1 and VSS2, if one fails, this is normal fall back logic,. in the 2 brains. (engine brain and tranny shifter brain) if the TCM cant see either VSS at all, it cant auto-shift, ever. (one more lil, clue)
on newer cars they do not use a speed head VSS, so have no backup. and cant auto shift when bad.
and the PCM sends constant errors for VSS as does the TCM.
chains are a unrelated topic, and next.
here is small pdf , showing both sensors. from the SPORT schematics, seen on mitchells.
http://jeepdied.com/look/24hr/96ab.pdf
short answer. VSS (veh, speed sensors, there are 2)
car has 2 vss,
the ECU and TCM can use either, both ECU and TCM when scanned tell you , when either are bad, (CEL glows, od lashes , scans told you this)
is the odometer dead too? if it dies the VSS1 in the head dies with it, and is most times a bad speed cable if both die (needle dead and odometer dead)
snapped cable cause 3 failures, VSS/needle mph/odometer. (can be the end of cable , clip broken , and is common)
if only the needle is dead, only, then the other 2 do work ok. see, the needle is magnetically driven, and can JAM and not effect the other parts that are pure raw mechanical drive.
easy no?> there are 3 things running off 1 cable, so monitoring all 3 , tells you what's up.
the TCM will use VSS1 and VSS2, if one fails, this is normal fall back logic,. in the 2 brains. (engine brain and tranny shifter brain) if the TCM cant see either VSS at all, it cant auto-shift, ever. (one more lil, clue)
on newer cars they do not use a speed head VSS, so have no backup. and cant auto shift when bad.
and the PCM sends constant errors for VSS as does the TCM.
chains are a unrelated topic, and next.
here is small pdf , showing both sensors. from the SPORT schematics, seen on mitchells.
http://jeepdied.com/look/24hr/96ab.pdf
http://www.fixkick.com