No communication with TCM & won’t shift

[Ωhm]

Let me know if you can or cannot open this.

 

_mj1988electricalmanual_1.pdf

[fixerupper88]

3 hours ago, JustEmptyEveryPocket said:

Considering what you have done so far, including swapping TCUs, I'm thinking its a bad wire somewhere. Follow Ohms recommendations. He is the genius around here for tracking down wiring problems.

I can believe it. I’m more of a part changer myself and I’ve done more electrical trouble shooting following his lead with this than I ever have before. guess ya gotta learn sometime. 

[fixerupper88]

49 minutes ago, Ωhm said:

Let me know if you can or cannot open this.

 

_mj1988electricalmanual_1.pdf 8.04 MB · 19 downloads

I sure can. Holy crap that will come is handy. Thank you big time. 

[Ωhm]

Compliments of the CC Forum. Helps everyone stay on the same page. It's not perfect, but its all we got.

[Pete M]

the link in my sig should have a thread that contains a lot of the digital manuals  

[omega_rugal]

20 hours ago, fixerupper88 said:

Now that you say that I did already try my buddy’s TCU and had the same result.

 

a confirmed working TCU does the same? then you have a bad wire somewhere

 

Quote

Unless there was some kind of procedure needed other then just plugging it in.

 

if it comes from the same year XJ/MJ then it should be plug n play, there are like 3 version that are not fully compatible, 88 - 95, mid 90s ones and 99+ ones

 

Quote

How do you check the harness? just find a diagram and check for continuity on each end? 

 

that would be the right procedure but you need a tester with some long cables

 

since you already confirmed that the tranny does shift when the solenoids get power why don't you install a 2nd gear switch? or better yet, a manual shifter?

[fixerupper88]

Well guys turns out was in fact the TCU. I had been watching a few on Ebay while driving by shifting manually and I finally scooped one up for 80 bucks and it works perfect.  thanks for all the help. Is there any way to fix up my old one be reprogramming or something or should I just chunk it out? 

[cruiser54]

Ya know, TCUs from different years will interchange, plug in, and not work.

The color of the harness end and TCU must match. I've seen blue and brown.