Stability System Disabled and Transmission

Hey Guys,

I've got a 2005 Yukon 4x4. Recently two warnings have appeared: 'Service 4wd' and 'Stability System Disabled'. These started appearing about a month ago, but never got around to getting it into a shop to check it out. Turning the power off and back on usually fixed the warnings until two days ago.

Now its constantly on and the lights on the 4x4 console have disappeared. It still felt like it was in 2 wheel high but my wife also said it started strange a few times, revving high before it shifted into 2nd. I have rarely used the 4x4 and even last month after a restart I was able to shift it between 2x and 4x modes.

We took it in to a good local shop and they said it was the transfer case and transmission. $500 for transfer and $2200 for transmission. Friend said the 4x4 and transfer electronics on these models sometimes go crazy and it shouldn't be the transmission.

We made an appt. with a dealer to get another opinion. Anything I can check on? The only Stability System posts I've found so far also had the low power mode warning, which we never have seen.

Thanks!

I am a mechanic, and my fiances yukon is having the exact same issues. I have heard of these issues before, but no one seems to have a viable fix. as this is my first crack at this I will tell you what I have done that has not worked so far. Keep in mind that major electrical systems such as this particular system are not really my specialty.

I have replaced the switch on the dash..... did'nt help. I have replaced the encoder motor on the transfer case..... did'nt help. I have replaced the stability system module under the drivers side dashjust above where your left foot would be ( did'nt have to disassemble the dash, its right there on the frame work of the dash). that did'nt help either.

I replaced the switch on the dash because the lights seemed dim, but were still lit up. which looking back all the switch is is a control not a computer module. I have replaced many encoder motors on older models, and it fixed the problem right away..... not the case here. after talking to a few other mechanics and looking at wiring schematics we thought it might be the stability system module. At this point I was willing to try anything, and puloing my hair out with this problem.

Any other info with this problem would be greatly appreciated as I am ready to pull out the dynomite!!!!

---------- Post added at 09:24 PM ---------- Previous post was at 09:10 PM ----------

Papagoat,
By any chance was any of the tire monitor system lights on? I also have a left rear tire pressure light on at the moment, and am wondering if that might ahve anything to do with the (stability system disabled) message.

We had this exact same issue on our 2005 this past Dec/Jan.

Service 4WD light started coming on sometimes, but 4WD still worked.

Then service 4WD light came on more frequently.

Next we were getting messages about stability system disabled and the lights on the 4wd postion switches were not lit up, or only the neutral light was lit, but it was not in neutral.

I did a bunch of reading on the subject and decided to try the switch replacement first. It was the least expensive option and many people reported this as solving their problem.

It turns out that the switch is often the problem on some of the older models, but in 04/05 GM fixed the problem with the switch so in my case I changed out a good switch with a new $90 one for nothing.

I next looked to the encoder motor. You can buy a genuine AC Delco one from Summit Racing if you give them the part number for your specific application (much cheaper than from dealer parts department and comparible in price to autoparts off brand pieces). There are different encoder motors, I first ordered the wrong one, it had a different plug on it so make sure you know which one you are ordering.

This is a very easy job to do if you are any kind of mechanically inclined. You have to remove the front driveshaft and it is just a remove and replace job.

Everything went back to normal in our case. For those who still have the problem, I do not know what else it might be off hand since I stopped researching the problem when our problem went away.

You do not want to drive too much with it acting up like that. I got ours done before this, but I read of several people saying the transfer case will shift into low range and the dash switch will not shift it back.