06 3/4 Suburban with push-button TC... Won't disengage 4wd...

[poorusername]

06 with push button TC case. Has been "switching" between modes occasionally and has recently gone into 4wd and will not disengage. Suspecting TC control module under the drivers side dash as most likely culprit. Anyone else concur?

 

[TJBaker57]

Has been "switching" between modes occasionall

Clarify?? Does this mean it has been changing modes without the buttons being pushed?

Personally I will always suspect wiring faults or terminal faults in harness connectors before suspecting solid state components.

It would not surprise me if say 80% or more of components replaced had nothing wrong with them and it was the harness connector terminals that were the real problem.

 

[poorusername]

Clarify?? Does this mean it has been changing modes without the buttons being pushed?

Personally I will always suspect wiring faults or terminal faults in harness connectors before suspecting solid state components.

It would not surprise me if say 80% or more of components replaced had nothing wrong with them and it was the harness connector terminals that were the real problem.

Yes, it has been switching between mode without any push of the button. And there have been instances where it would switch out of a mode that I put it in and I would have to switch it back to that repeatedly. It was suggested to me to check wiring harness at the transfer case four signs of debris or water damage.

 

[Mooseman]

I would also check the switch itself. Although I`m not entirely familiar with this particular model, it could be the switch that has dirty or corroded contacts. If you can get it into 2WD, try unplugging the switch and see if it happens again. If it does, I would start checking the wiring more deeply. I doubt it's the encoder motor as it only moves if commanded by the TCCM or possibly a short somewhere sensing power to it.

Beyond that, unless @TJBaker57 has something that can be done with a Bluetooth OBD adapter and an app, this may require a more advanced scan tool to see what the TCCM is seeing from the switch and the encoder or if the TCCM is at fault and/or try to command the encoder motor.

Are you getting a service 4x4 light?

 

[poorusername]

Are you getting a service 4x4 light?

Are you getting a service 4x4 light?

Yes I am.

 

[mrrsm]

As an "Experiment" in Testing the historical accuracy of GPT4ALL (a Large Language Model Artificial Intelligence...FREE to Download, Install and USE OFF LINE) ...I Copy-Pasted your Post #1 Query into "IT" noting that the "IT" in this case was the Llama B3 8B Instruction (128 KB of Prompt Length) and THIS is what "IT" came back with:



Note that we have tried this on other occasions and "IT" proved helpful to some degree... even more accurate than OpenAI's responses. But I stress here that NOTHING Beats the "Hive Mind" behind the responses coming from the Experienced Members at GMT Nation ...for THE Best Ideas and Solutions...:

https://gpt4all.io/index.html?ref=localhost

 

[Mooseman]

Yes I am.

So this would tell us there is a detected fault in the system. Again, maybe @TJBaker57 can provide some instructions on how to scan for TCCM codes. Do you have a Bluetooth OBD adapter? if not, the Veepeak from Amazon is @TJBaker57 's favourite and he can guide you on how to use it to scan with it.

 

[mrrsm]

These Images come from a Snap-On Vantage Pro Diagnostic Dual Graphing DMM, "O" Scope and "Guided Component Information and Tests" feature that seems more precise for Diagnostic and Testing purposes than what GPT4ALL had to say. Sorry about the "Shaky" Camera Shots... I was doing this with the Gear sitting in my lap.

This information is SPECIFIC to your 2006 Chevrolet Suburban, however if I got the VIN Engine CID and Transfer Case selections off... Let me know and I'll run them "Through the Snap-On Ringer" once again.

Two Batches of Images Follow (First...20)



The Rest Follow in the Next Post...

 

[mrrsm]

Last Images...



Hope it Helps...

 

[poorusername]

Last Images...

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Hope it Helps...

Very interesting. Thank you for running it. THe only thing I didn't mention because I didn't think it would matter is that it is an 8.1L truck. Will look through this during lunch.

 

[TollKeeper]

The push button 4x4 systems did have issues in the controller. Thats why the pushbutton controller can be had so cheap on Amazon $18.00, if you have the A4WD transfer case.

https://www.amazon.com/dp/B07DKCR6XP/?tag=gmtnation-20

I am thinking with the 8.1 you have the selectable transfer case which is a different pushbutton controller. $15

https://www.amazon.com/dp/B09KNYTGBF/?tag=gmtnation-20

The 4x4 TCCM (transfer case control module) is quite a different story, at a cost of $544 (or more)!

 

[Mooseman]

However, before bringing out the parts canon, a reading of codes would be good to confirm.