Stuck in 4WD. Any help?

[rockola1971]

I got the new encoder both hooked up to the TC and hooked up electrically.

New TCCM is installed as i tested wiring integrity to verify it was good.

Now, the issue is that the new TCCM is throwing code U1000. It takes a good 5 minutes from the time i turn the key to RUN for all of the lights to go out on the 4WD switch. Getting farther, but still, stuck.

It shifts beautifully between whatever gear I select after it eventually works. No issues.

U1000 is class 2 comm problem. Likely loose, corroded, broken ground drivers side above frame near firewall.

 

[TheEnder53]

He said 2001 Tahoe LS 4X4 in post #13.

@TheEnder53 what TCCM did you get? I know the later Tahoes need to have them programmed, or be purchased as not needing to be programmed. Not quite sure about yours.

I got a remanufactured Cardone unit.

Turns out it was bad. This morning would not initialize and the selector switch was stuck with all the lights on and the truck was unable to drive (felt like it was stuck in 3rd gear.)

Returned the Cardone TCCM. Got a Dorman TCCM (Pre-programmed for RPO Code NP8) and it has worked flawlessly ever since. No more 4WD codes. Nothing. Switches still blank out occasionally, but I think it has to do more with the fact that they’re bad. If i press in the middle of the switches the 2HI light comes back. Not going to worry about it any time soon.