2005 Suburban Service 4WD issues

[TIMtheELT]

I have a 2005 Chevy Suburban that has been frustrating me with a "Service 4WD" and a "stability control system disabled".

 

I've been troubleshooting it for a while and I have been doing the various things that I find on the interwebs.  Some work for a while and some do nothing.

 

• I removed and cleaned some grounding switches under the driver's door.  - Nothing changed.
• I replaced the selector switch next to the steering wheel. - This seemed to work, but then the errors came back.

 

At this point, the drive system started randomly shifted between 2WD and 4H or 4L.

 

• I assumed this meant that the encoder motor has gone bad.  I purchased and installed a new one and now I only get a red light on the selector switch.

 

I'm not sure if something else is wrong or if I have a bad replacement encoder motor.

 

I have reached out to the online parts store to see what they say and don't have an answer from them yet.

 

I scrolled the forums and went cross-eyed before finding a thread that talks about this.

 

Anyone out there that maybe has gone through the same thing and come out on the other side?

 

Thanks!

[Supreme Pizza]

Bummer, your problems sounds like may others. . From my experience, these rigs have questionable electronics. It keeps the trade-ins coming in and the new rigs going out. For your situation, you could try putting the old encoder motor back in as a test. I replaced my 4x4 switch on the dash, and surprise surprise - just like yours - the problem went away for a week, then came back. 

 

   I have other issues that are similar. Thinking about replacing the throttle body and PCM. Its kinda like throwing shit at the wall just to see what sticks. 

[Kandie Wood]

I too have a 2005 Suburban 4x4,mine is the flex fuel.. Anyhow at almost 180k same exact thing happened to mine. I would be driving and poof running 65mph it would engage 4 low. Or switch to Auto. There would also be times when I needed 4x4 it would not engage at all but would act like it. This truck had me so mad crazy I was ready to let it fall off a cliff.

  It spent 6 weeks at the Chevy Dealership, not a big deal they let me pick anything I wanted to drive. Big mistake for this girl.. Anyways, they checked everything from the transmission,to the rear axel.and finally the shop foreman was driving it home and poof finally engaged on its own. Turns out the issue was about 1,000 bucks to fix.. Ended up having to replace the control buttons for the 4x4 and the control module mother board for the 4x4. Now it sets at 230k and 4x4 works amazing... 

 Fyi, if you just replace the buttons it will not change anything,if you just replace the mother board nothing..for some odd reason both have to be changed. 

 So far most expensive repair to date. Now just to get these damn spark plug wires off and I will be extremely happy... Good luck...Hope this helps...