is my TCCM toast?

[vaeevictiss]

2006 Sierra 1500

So for about a year ive been having the intermittent "Service 4WD" message. Normally, shutting the truck off and turning it back on would fix it. Well today that wasnt the case. I started browsing and found the 3 causes are either the button pack, the TCCM, and the encoder motor.

Well i went to look at the TCCM since it seemed the easiest after already checking the button pack and reflowing the solder which had no effect. I unplugged the harnesses from the TCCM, plugged them back in, and to my surprise it was worse. Same message, but now no indicator lights on the button pack.

I tried the fuse pull and battery disconnect tricks and those did nothing either. Then for the hell of it, while it was running, i pulled one of the TCCM harnesses out, and plugged it right back it and the lights came back on. While in park, i went thru the range of gears and everything worked. I decided to take it up the road so while in 2wd, i shifted to 4hi at low speed to make sure it worked while moving. That went fine. After being satisfied thinking i fixed it, i decided to take it back home. I went back to 2wd, and right after it made the switch, the lights went back out and the message came back on....dammit!

So seeing as tho all this revolved around me messing with the TCCM, would it be safe to assume that is the issue? Also, if it is, and i pick one up from parts direct or some place, is it just plug and play or does the dealer need to program it?

any help would be great as this has finally got me very frustrated lol.

[gmtech4]

the code has to be diagnosed first ,,,get it scanned ,get a manual online and diagnose it or.....do what ya want