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AW4 weird problems or bewitched

U

uniteam

NAXJA Forum User
Location
Mexicali,Baja California,Mexico
My friend has near to 2 months with a transmission nightmare..

He has a 1996 XJ with AW4 (Automatic) TC 231 and 3.55 gears

He has already changed with diferent mechanical shops:

1.- A Used Transmission
2.- Torque Converter
3.- TCM
4.- PCM
5.- New Solenoids
6.- Park/Neutral switch
7.- TPS
8.- VSS

and the problem still there...

Here are the symtoms..

sometimes when he put the gear selector on D, it starts on 3rd or 4th..
But sometimes starts good on 1rst and enter all the rest of gears fine, but suddenly starts to make weird downshifts and upshifts..

When he has some luck, it starts fine, make upshifts fine, but when a few minutes of run fine on overdrive the trans start take off the OD leaving it on some cases only in 3rd gear..

When this problems are present, he solve the situation temporary turning off the engine and starting again..

What do you think??

thanks
 
Last edited:
I would guess it is either the TCU or the tranny kickdown cable out of adjustment. If it is the TCU, he can disconnect it and manually shift through the gears.
 
Has to be like a loose connection or bad wire in the wiring harness anywhere between the TPS, TCU, NSS, Transmission itself, and the PCM.

Only way to find it it is going to be ignition in the run position, engine off, with a DMM wigling the wires and connectors. Check wires near the exhaust for burned wires. Also verify all the component grounds are good, like TPS, PCM, and TCU ground wires.
 
uniteam said:
ok, Where is located the TCM fuse exactly? Under the Dash on passenger side, or it is on the engine section ?

thanks I will say him this suggestions..
Click to expand...

Not sure on a 96. The older ones had a fuse in the wiring harness just before the TCU. There may be a fuse in the fuse box?
 
This has just happened to me - I have a 95 Sports 4.0l Auto .. Will run normal for a few days the I'll stop at a set of lights and no kickdown happens and have to change to 1-2 Manually or drive off in 3rd !! - My tranny guy diagnosed a faulty solenoid and wants to replace it - on reading all of the above should I be replacing the TPS and TCU ? Cheers ..
 
Last edited:
Mandrake said:
This has just happened to me - I have a 95 Sports 4.0l Auto .. Will run normal for a few days the I'll stop at a set of lights and no kickdown happens and have to change to 1-2 Manually or drive off in 3rd !! - My tranny guy diagnosed a faulty solenoid and wants to replace it - on reading all of the above should I be replacing the TPS and TCU ? Cheers ..
Click to expand...

Maybe neither. Check the wiring, connectors, and grounds first.

Could be and sounds like a loose connection or wire somewhere. NSS is a suspect also as it tells the TCU where the shifter is located. NSS, TPS, loose grounds and loose connections are the most likely suspects for intermitent problems.
 
Cheers Ecomike - Not being very handy with vehicle maintenance I'll pass this on to my service mechanic and see if he can spot it ...
 
Mandrake said:
This has just happened to me - I have a 95 Sports 4.0l Auto .. Will run normal for a few days the I'll stop at a set of lights and no kickdown happens and have to change to 1-2 Manually or drive off in 3rd !! - My tranny guy diagnosed a faulty solenoid and wants to replace it - on reading all of the above should I be replacing the TPS and TCU ? Cheers ..
Click to expand...

It's possible it's a bad soleniod, but also just as likely to be a wiring problem or intermittent power getting to the TCU.
 
I'd be checking the wiring also. Does the check engine light come on? If the TCM gets no signal from the TPS, it defaults to a half throttle setting. There may be something similar happening if the speed sensor craps out.
Check for codes, by the key on key off method and then disconnect the battery and clear the codes. A stored code may cause a fault.
96 is a transition year. The 97 variety has a history of bus faults.
A scan tool check may show "P" code faults that may be helpful in diagnosing the problem.
Like Ecomike said, grounds are a good place to start when the gremlins start appearing.
 
8mud - I checked the engine light blink code and it came out as 5 5 !! which i believe means "nothings wrong" !! The guys are looking at it now so hopefully it will be fixed and I can drive home from work....Cheers ..
 
Just to complete the thread - My transmission guy replaced the solenoid "set" and assures me everything is OK now.... So far he's right ....
 
Mandrake said:
Just to complete the thread - My transmission guy replaced the solenoid "set" and assures me everything is OK now.... So far he's right ....
Click to expand...
Just curious, how much did it cost you to have those replaced? Similar probs with my 94 xj. I still have yet to check the wiring though. Thanx
 
Not sure if this will help you but the total bill was $640.00 Aust ($550.00 US) - That included the new fluid , 3 solenoids and labour . .
 
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