I feel you, the manual seems like it was written so a programmer could code for a robot, versus being written for a human to use effectively.just seems strange that there would be no other codes, I have the service manual in pdf but it's not linkable so it makes it very difficult when it say's to reference "x" and you cant go directly there and it has 10,000+ pages
In the transfer case debug section I looked at, the only codes are B07xx and C03xx, no U codes at all. The one exception is a B2725 which pertains to the switch circuit, if that code is stored, then it sends you down a path to debug the switch (and all paths seem to lead to the switch being replaced if the wiring checks), otherwise it all seems to be centered on an endpoint of replacing the shift control module.