WJ CRD diagnosis just got a big boost:
The people over at jeepswj.com wrote a program which can read and erase the ECU and TCU error codes. No more DRBIII to diagnose transmission problems.
You need to download their software, which is on the website:
http://www.jeepswj.com/software/
This is the interface I've used:
http://elm327.ro/blue21
For some strange reason it took quite a few tries to connect, and that happened every time and on two cars.
These are the codes on mine (all transmission faults were fixed at some point)
The other car which I've tested was in permanent limp mode because of N2/N3 sensors. Conductor plate was changed but limp mode could not be cleared without the scanner.