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AW4 problem

Evan463

NAXJA Forum User
Location
Rhode Island
(98XJ 4.0 Aw4) My Aw4 is not shifting into (over drive) and is not down shifting to first when stopping (tries to start off in third). However it shifts manually, 1-2= first gear, 3 = second gear, D(overdrive) = third gear. Just finished putting in a transmission control module from another 98 and nothing has changed. Need thoughts, ideas, any input would be helpful. thanks.
 
check the power wire going to the TCU-- there should be an inline fuse for it. If it has blown, you'll only be able to manually shift like you've got.
 
Just checked mine the harness is wrapped in plastic then goes through the tunnel (tcu mounted on driver side of tunnel above gas pedal on 98+) does not appear to be any type of fuse there.
 
Start at the beginning, why did you install a different TCU ?

Did you test the NSS or the TPS ?

Fuses are in the fuse box.
 
started by reading about 100 threads on here all describing the same problem im having all of which said the same thing (TCU).

if the fuse for the tcu is in the fuse box then its def not blown. (checked all fuses before i did the different tcu)

i have not checked nss (will that effect shifiting like that?)

throtle position sensor and transmition speed sensor are next (going by troubleshooting in fsm.)

sound reasonable?
 
In the 2000 wiring diagram, a pink wire should have 12V all the time (from a Power Distribution Center fuse), and dark blue/white wire should have 12V when the key is in start/run (from a Junction Box fuse). You can also check the ground. Usually that is the black wire.

You say it shifts manually, so that should rule out the NSS.
 
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In the 2000 wiring diagram, a pink wire should have 12V all the time (from a Power Distribution Center fuse), and dark blue/white wire should have 12V when the key is in start/run (from a Junction Box fuse). You can also check the ground. Usually that is the black wire.

You say it shifts manually, so that should rule out the NSS.

Thats what i was thinking with the nss.
thanks for the wire hints ive been trying to find the page with that diagram on it but have been having trouble.

going to get out there first thing in the am and check power. thank you.

happy new year.
 
Just checked for power. i have 12v at the pink wire. 12v at dark blue/white wire with the key on. and have ground on black/white wire.

tps?
transmission speed sensor?
or how about brake switch?
 
new possible (symptom). im getting the occasional no start like a bad NSS. everything comes on like normal with ignition on go to start and nothing happens the only light that is on is the BRAKE light on the dash. can hear a slight click to my right but cannot tell where it is coming from. shift into neutral. same thing shift back into park and push forward on shifter a little harder then normal and it will start. while this is happening there is no increased load on battery. meanning starter isnt even trying to engage voltage stays steady at 12.4.

so that to me sounds like a bad NSS. just would like more opinions before i have to dish out 250 for one. and also if you think this will solve my shifting problem.
no check engine light is on. or has ever been on for that matter not to sure if it works to be honest.
 
Take it apart, clean it, regrease it (dielectric) and reassemble. Did you get the right 98 TCM? Part # 56041068 or 56041386AA.
 
part numbers are the same on the tcm except for the one from the junk yard was AB it was out of a 99, they checked on there computer and also called a few different parts stores and all of them say the same. (damn hope there all not wrong, but wouldnt be the first time ive been mislead by numerous people) ((dont have jeep here its in the shop at work so cant get the numbers off of it but know they matched minus the AA to AB))

stupid question. whats dielectric?

and looks like i know what im doing this weekend now haha.
 
part numbers are the same on the tcm except for the one from the junk yard was AB it was out of a 99, they checked on there computer and also called a few different parts stores and all of them say the same. (damn hope there all not wrong, but wouldnt be the first time ive been mislead by numerous people) ((dont have jeep here its in the shop at work so cant get the numbers off of it but know they matched minus the AA to AB))

stupid question. whats dielectric?

and looks like i know what im doing this weekend now haha.

Problem is it's for a 99-01. The 98 one is specifically only the two #'s I gave you. It DOES NOT supercede to an "AB" part #. This may because in 99-01 AW4's use 2 speed sensors for the trans controller vs. 1 on 87-mid98/99 and the 99 TCM is looking for a sensor you may not have on your trans.

Dielectric grease, special for electrical contacts.
 
sooo there all wrong. that sux. however, if its the nss causing my nightmares then all i have to worry about is getting my money back for the tcm. right? or is there still a possibility that i still have a bad tcm and just have the wrong one
 
sooo there all wrong. that sux. however, if its the nss causing my nightmares then all i have to worry about is getting my money back for the tcm. right? or is there still a possibility that i still have a bad tcm and just have the wrong one

It's possible the TCM is bad or it's a sensor/wiring/fuse problem. I would work on the NSS/gear selector switch but you may have some other problem. Di you ever try to pull codes with a scan tool?

This info (following) is kinda useless based on what I found out looking at the disgrams. JB=right kick panel fusebox inside and PDC=underhood fusebox . On a 98 fuses that feed or can affect the trans are JB # 25 a 15A fuse (but you wouldn't be able to take it out of park/shift lock solenoid), JB # 11 a 20A fuse (but the engine wouldn't run if this was blown) , PDC # 16 a 15A fuse (dome lights would be out if this was blown),
 
The wiring does show a 98 as having 2 speed sensors but for some reason the parts catalog says the 98 TCM is for a 98 only. Looking at the 2 years wiring for the TCM connector honestly I can't see why it wouldn't work using a 99 TCM though. It's got to be wiring, a solenoid in the trans, or something. Doesn't seem to be a TCM. If you know anybody with the same year XJ use the TCM you got it thiers and see if it works. If it does then it's not the TCM.
 
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i have tried in the past to pull codes with a scan tool (correction the wonderfully helpful 18 year old kid at auto zone tried to pull codes) however it would not work (i tried myself after ) im not entirely sure that i have power going to that plug (for lack of a better term) that was a few years ago though and havent had any other problems
 
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