2008 GMC Yukon stabilitrak & traction control issues?

[Megusta]

Hey everyone. So yesterday I drove to a doctors appointment & when I was in the parking lot, I started messing with the 2wd & 4wd knob (don’t know why I did that). But all the sudden I got stuck in 4wd low & I couldn’t get it back to 2wd. The traction control light & stabilitrak light came on (no engine light). I started having very rough shifts & rough acceleration. I had to get towed home. Today I went to autozone to get my car scanned (no codes). So I drove back home & as soon as I get back in the driveway, I started messing with the 2wd & 4wd knob again, I was able to get it back into 2wd again. The traction control & stabilitrak went away on its own & the car is driving normal again as of right now. I hope that never happens again. What could the issue have been? Anyone who has had this problem, please let me know. Thank you.

 

[Doubeleive]

View attachment 424431View attachment 424432Hey everyone. So yesterday I drove to a doctors appointment & when I was in the parking lot, I started messing with the 2wd & 4wd knob (don’t know why I did that). But all the sudden I got stuck in 4wd low & I couldn’t get it back to 2wd. The traction control light & stabilitrak light came on (no engine light). I started having very rough shifts & rough acceleration. I had to get towed home. Today I went to autozone to get my car scanned (no codes). So I drove back home & as soon as I get back in the driveway, I started messing with the 2wd & 4wd knob again, I was able to get it back into 2wd again. The traction control & stabilitrak went away on its own & the car is driving normal again as of right now. I hope that never happens again. What could the issue have been? Anyone who has had this problem, please let me know. Thank you.

First guess is transfer case encoder motor
2nd guess front differential actuator
but given the lights, probably first guess
btw, those errors are not obd, so a regular code reader won't work and a more advanced scanner that can read body codes will be needed and the error should be active (light on) to read it in most cases, but there "could be" a history code saved.
why gm couldn't just add a 1kb line of code or less to give a more detailed definition of problems is anyones guess

 

[Fless]

All normal and operator error. The owner's manual will help, pull it out of the glovebox or get it here (unless it's a Yukon, then use the GMC site): https://www.chevrolet.com/bypass/pc...ging/MANUALS/0/MA390/en_US/2.0/2k08tahsub.pdf

Read it.

And get familiar with how to switch in and out of the drive modes (here's how to go into 4LO; the next page in the manual tells how to get out of it):

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.

 

[Doubeleive]

All normal and operator error. The owner's manual will help, pull it out of the glovebox or get it here (unless it's a Yukon, then use the GMC site): https://www.chevrolet.com/bypass/pc...ging/MANUALS/0/MA390/en_US/2.0/2k08tahsub.pdf

Read it.

View attachment 424433

And get familiar with how to switch in and out of the drive modes (here's how to go into 4LO; the next page in the manual tells how to get out of it):

View attachment 424434

it shouldn't have been "stuck" though, that makes me think the encoder motor wasn't changing/stuck but after several tries eventually did move back to correct position and problem went away.

 

[Fless]

it shouldn't have been "stuck" though, that makes me think the encoder motor wasn't changing/stuck but after several tries eventually did move back to correct position and problem went away.

It was probably taken out of neutral and that won't allow it to change out of 4LO.

 

[Doubeleive]

It was probably taken out of neutral and that won't allow it to change out of 4LO.

heck anything is possible I suppose, lol
I guess we can presume he drove it to autozone in 4low
not sure how the 4wd alerts you on the 900's on the k2 Silverado it will tell you on the DIC that you need to switch to nuetral for 4lo, otherwise it stays in 4hi and just blinks
the denali has no switch...

 

[Megusta]

First guess is transfer case encoder motor
2nd guess front differential actuator
but given the lights, probably first guess
btw, those errors are not obd, so a regular code reader won't work and a more advanced scanner that can read body codes will be needed and the error should be active (light on) to read it in most cases, but there "could be" a history code saved.
why gm couldn't just add a 1kb line of code or less to give a more detailed definition of problems is anyones guess

I got under the car & that’s the same part I thought about unplugging. But instead I reseted the ECU & drove to autozone & back. & then everything started working fine after I turned the knob back into 2wd. Pretty weird, but I’ll keep an eye out for it.

 

[Megusta]

All normal and operator error. The owner's manual will help, pull it out of the glovebox or get it here (unless it's a Yukon, then use the GMC site): https://www.chevrolet.com/bypass/pc...ging/MANUALS/0/MA390/en_US/2.0/2k08tahsub.pdf

Read it.

View attachment 424433

And get familiar with how to switch in and out of the drive modes (here's how to go into 4LO; the next page in the manual tells how to get out of it):

View attachment 424434

Very helpful, thank you.

 

[Megusta]

Thanks everyone for being so helpful.

 

[Doubeleive]

I got under the car & that’s the same part I thought about unplugging. But instead I reseted the ECU & drove to autozone & back. & then everything started working fine after I turned the knob back into 2wd. Pretty weird, but I’ll keep an eye out for it.

if the encoder motor was stuck it would likely explain all the wierd stuff because the computer is trying to do one thing but the vehicle is not giving the correct data,
like wheel speed vs differential state or something to that effect... thereby confusing the transmission
if you have access to a scanner that can read body codes, there could be a historical code saved when the error occured "maybe" sometimes they are saved and sometimes not.
the code is not obd. sometimes you have to scan it while the error is present.

 

[Bobio2003]

View attachment 424431View attachment 424432Hey everyone. So yesterday I drove to a doctors appointment & when I was in the parking lot, I started messing with the 2wd & 4wd knob (don’t know why I did that). But all the sudden I got stuck in 4wd low & I couldn’t get it back to 2wd. The traction control light & stabilitrak light came on (no engine light). I started having very rough shifts & rough acceleration. I had to get towed home. Today I went to autozone to get my car scanned (no codes). So I drove back home & as soon as I get back in the driveway, I started messing with the 2wd & 4wd knob again, I was able to get it back into 2wd again. The traction control & stabilitrak went away on its own & the car is driving normal again as of right now. I hope that never happens again. What could the issue have been? Anyone who has had this problem, please let me know. Thank you.

 

[Bobio2003]

Had an issue with my 2009 Yukon SLT where the cruise quit working and antilock brake light came on along with the stabilatrack light. Turned out to be the brake light switch. If that is your problem, make sure to get the correct switch. There are several switches available depending on your options.