auto swap is done, but has an issue

[Cabz]

Well I finaly got around to swapping the aw4 into my MJ :D so far it works like a champ, well with one issue :roll: the TC won't lock up ( and no backup lights ).

I checked thew brake switch and it is fine but when I have the scanner on the heep it shows the brake pedal is activated and the lock up is off.

 

any ideas on what this could be? ( by the way this is an 88 MJ 4.0 with an 89 harness and aw4 )

[90PioSport99]

Did you adjust the TV cable properly?

[Cabz]

Did you adjust the TV cable properly?

 

yup everything is adjusted as the FSM said to do , thats why this is kind of a headscratcher .

[LEAD_NOT_FOLLOW]

Reverse lights are activated by the NSS.

 

You said you did the swap. What were you swapping from and did you add all the wiring and the new (from the AW4) TCU?

 

The TCU is programmed to force torque converter lockup when engine RPMS's are above a certain point (not sure exactly what RPM though?), and when you're at wide open throttle (WOT). As far as the torque converter lock goes. Solenoid 3 is unique, in that it only controls torque converter lock functions.

 

Maybe the AW4 Manual on GLXJ would be of help? It's under the Transmission and Transfer Case section.

 

http://www.greatlakesxj.com/tech.html

[LEAD_NOT_FOLLOW]

I should also add that you can test the TC by applying power (12v) to the white/black wire at the TCU (C14) to see if Sol. 3 is working.

 

Wiring diagram if you want it - http://www.greatlakesxj.com/tech/TCU4.jpg

[Cabz]

I swapped from a dead pukegoat to the aw4 , I also swapped in all the wiring harness , pcm and tcu from the same vehicle.

The reverse lights used to work on the old setup , what i think is wrong there is the wire for it is in the wrong spot on the plug ( one of them anyway ) they used to like to change simple things like that from one year to the next on the old heeps .

 

I will check out that link , thanks :D

Reverse lights are activated by the NSS.

 

You said you did the swap. What were you swapping from and did you add all the wiring and the new (from the AW4) TCU?

 

The TCU is programmed to force torque converter lockup when engine RPMS's are above a certain point (not sure exactly what RPM though?), and when you're at wide open throttle (WOT). As far as the torque converter lock goes. Solenoid 3 is unique, in that it only controls torque converter lock functions.

 

Maybe the AW4 Manual on GLXJ would be of help? It's under the Transmission and Transfer Case section.

 

http://www.greatlakesxj.com/tech.html

[TNT]

Reverse lights are activated by the NSS.

 

You said you did the swap. What were you swapping from and did you add all the wiring and the new (from the AW4) TCU?

 

The TCU is programmed to force torque converter lockup when engine RPMS's are above a certain point (not sure exactly what RPM though?), and when you're at wide open throttle (WOT). As far as the torque converter lock goes. Solenoid 3 is unique, in that it only controls torque converter lock functions.

 

Maybe the AW4 Manual on GLXJ would be of help? It's under the Transmission and Transfer Case section.

 

http://www.greatlakesxj.com/tech.html

 

It unlocks under heavy throttle, it's not meant to deal with high engine loads. It also unlocks anytime the brake is used.

[TNT]

Well I finaly got around to swapping the aw4 into my MJ :D so far it works like a champ, well with one issue :roll: the TC won't lock up ( and no backup lights ).

I checked thew brake switch and it is fine but when I have the scanner on the heep it shows the brake pedal is activeated and the lock up is off.

 

any ideas on what this could be? ( by the way this is an 88 MJ 4.0 with an 89 harness and aw4 )

 

It's the brake switch code that explains wht you aren't locking up the converter. I'm not sure if the switch is the same on a auto as a stick. Find a wiring diagram ang run a test on the brake switch circuit. I bet this is your problem.

[oldjeep]

Are you sure that the TCU is hooked up to the switched side of the brake light switch? The switch is the same on an auto vs stick, I didn't have any problems using the same one when I swapped on my kids 90.

[Cabz]

Are you sure that the TCU is hooked up to the switched side of the brake light switch? The switch is the same on an auto vs stick, I didn't have any problems using the same one when I swapped on my kids 90.

 

yup i even compared it to my daugther xj and it is wired and workin right

[oldjeep]

Are you sure that the TCU is hooked up to the switched side of the brake light switch? The switch is the same on an auto vs stick, I didn't have any problems using the same one when I swapped on my kids 90.

 

yup i even compared it to my daugther xj and it is wired and workin right

 

Have you checked the brake signal pin on the tcu harness with a voltmeter? Maybe there is a short? Otherwise, It sounds like you might have a bad TCU if it thinks the brake lights switch is on when there is no voltage present.

 

Does your daughter have a 90 or older that you could swap in her TCU?

[90PioSport99]

Another thing that just popped into my head. Have you checked all associated fuses? The one inline with the TCU and the 7.5A one in the fusebox? I assume you probably installed new ones, just thought I'd throw another idea out there.

[Cabz]

Thanks for all the sugjestions guy, I got it figured out .

It turned out to be the clutch/trans switch out of adjustment. I didnt realize that they had a mixed in switch setup . the SW I am refering to is the one up high , white plastic with a vac line on it I thought this was for crusie only.

 

The reverse lights turned out to be juts the NSS out of adjustment ( the switch is kinda crappy anyway ) .

 

but as of now she's all done and works like a dream :D

 

thanks again