2008 Silverado no 4x4 and no indicator light

[Erick Baccus]

So long story short, my transmission went and I replaced that. Took it for a test drive and transmission worked great, and the 4x4 worked. But, I used my scanner (Snap-On Modis) and went and relearned the transfer case motor for some reason and it pretty much disabled my 4 wheel drive. So, I checked the ground under the drivers door, and even though it was good, I removed it and cleaned the connection. I also installed a new transfer case motor. I included a picture of the volts that my transfer case motor connector has. One thing I want to mention is the power for Motor A shows power but on my power probe it beeps, not constant. So I don’t know what that means. Right now I’m at a loss and usually I can pin point the problem. On the picture with the references the side with the bad is my truck. The good, is my brothers truck which is the same truck and those are his numbers. 

Edited December 24, 2021 by Erick Baccus

[Supreme Pizza]

55 minutes ago, Erick Baccus said:

So long story short, my transmission went and I replaced that. Took it for a test drive and transmission worked great, and the 4x4 worked. But, I used my scanner (Snap-On Modis) and went and relearned the transfer case motor for some reason and it pretty much disabled my 4 wheel drive. So, I checked the ground under the drivers door, and even though it was good, I removed it and cleaned the connection. I also installed a new transfer case motor. I included a picture of the volts that my transfer case motor connector has. One thing I want to mention is the power for Motor A shows power but on my power probe it beeps, not constant. So I don’t know what that means. Right now I’m at a loss and usually I can pin point the problem. On the picture with the references the side with the bad is my truck. The good, is my brothers truck which is the same truck and those are his numbers. 

 

 

 

Lots if good info.

 

I cant use any of it to help you, but someone else might be able to.

 

All I can suggest is that you check any wiring connections that might have been disconnected during the repair. Battery connections, encoder motor connections, grounds, sensors, etc.

[Erick Baccus]

I’ve disconnected all the connectors at the fuse box, all the way back to the transfer case. Made sure no pins were bent or pulled out. Applied dielectric grease and reconnected them. I’ve heard there are 3 grounds for the 4wd system, I only know of the one under the drivers side door. Not sure where the other two are. Is there one on the transmission bell housing bolts? 

[Supreme Pizza]

From the post, its sounds like you re-learned the encoder motor when it was not required, and the relearn caused it to stop functioning properly, is that correct? Am I reading the post incorrectly?

[Erick Baccus]

That is correct 

[Supreme Pizza]

Ah. If that is the case, I would say that you should repeat the relearn procedure multiple times to see if you can it to work properly. I have done re-learns on other GM stuff, and sometimes it takes several tries before it works. I have re-learned the resistors on the VATS GM security ignitions, and it never works on the first try. Also, you have to follow the instructions to the letter. Re-learn sometimes requires special conditions before it will work properly.

[Erick Baccus]

If tried to relearn it many times after. But it won’t because of the fault codes. Clear the code, pops back up right away. It’s frustrating 

[Supreme Pizza]

If the problem started right when you did the re-learn, then it has to be related to that somehow. Did you try going back to the original encoder motor?

[Erick Baccus]

Nope. Cause I had to use it as a core. 

[Supreme Pizza]

I always keep my cores for at least a week or two. That way I can return the new one of needed, or to swap back and fourth for testing purposes. I also always buy stuff on Amazon when possible, because its WAY cheaper, next day free delivery, and they do not require a core. Anyway, if you buy from the auto parts store - then you can return the core two weeks later and get the money, doesn't need to be done on the spot.

 

Amazon is about $100 for an encoder motor with no core. What did the auto parts store want for it?

[Erick Baccus]

I warrantied my old one. AutoZone told me to warranty it they would need the defective one. Otherwise o would have had to pay full price until I gave them the old one. 

[Supreme Pizza]

Ah, so it was a free replacement

 

That's good.

 

Out of curiosity, what do they normally charge for them?

 

 

 

 

[Erick Baccus]

$379.99 list for a dorman. 

[Supreme Pizza]

Sounds about right for retail.

 

It might be necessary to pay for a diagnostic.

 

If the codes are preventing programming, and replacing parts and checking connections doesn't fix the codes, then there are not a lot of options left. I would just start Googling the codes and symptoms. A forum is a great resource, but you would need to find someone that has experienced the same problem and solution, or get lucky enough to have a Chevy dealer tech see the post and be willing to offer advise. I assume that the Chevy Dealership mechanics are not allowed to post free advise in forums though. If they are allowed to, then.... SPEAK UP, help this guy out !!

 

 

[Erick Baccus]

Got it all figured out. It was the transfer case control module. I took the one out of my brothers truck (which is identical to mine) and everything worked right away. So now I just have to order one and put it in. It’s Dorman part number 599-192. $119.99. And a $205 core.