Very Hard 1-2 shift, Service Stabilitrak Light

[BanditHoe]

I'm going to check mine tonight with the TechII, but mine started doing this as soon as the engine misfires came on. Last night I determined cylinder #4 was misfiring, started swapping the wires, plugs, coils, etc. and found the plug in cylinder #4 was bad. I've got new plugs, so i'll know tonight if that's what is causing it. But many times if the computer detects a misfire it can also affect the transmission settings - I went though this in my 98 Regal with TCC lockup and misfires.

Option two is the vehicle dynamics control module above the rear axle. Last year my truck died and wouldn't start - like somebody else described. In these trucks when one of the many modules (upwards of 7 - depends on options.) goes down it drives the system crazy. The ones that commonly fail in my climate are the fuel control module, dynamics control module, radio module or airbag module (under the drivers seat). I unplugged and removed my dynamics module last year and the truck started and ran good. That's why I know mine isn't because of that module, but it could be for others. The replacement dynamics module is $350 online, $500 at the dealer. The other reason i'm encouraged that this could be the failure point of many of the described failures is because the yaw sensor (used for stability) in the steering column communicates with this module; yaw sensors are also a common failure as well.

Option three, and possibly my issue, is a wheel speed sensor. This is easy to diagnose with a TechII or scanner. Watch the wheel speeds as you drive and replace the erratic sensor.

Most of the described problems I would lean towards a failing module, likely one of the ones I listed. When mine went, the truck went nuts, gauges flashed, shifting weird, every light on the dash lite, etc. Start by unplugging them one by one and drive in between to determine which one it is.

 

[BanditHoe]

Just to keep this updated in case others need input on this. My misfire definitely caused my issue. From what I could tell from the GM information is the the EBCM (electronic brake control module) uses the wheel speed sensors to also monitor misfires, this is done to make adjustments (stability/traction) when rough road conditions are met.

Weird, but all of my concerns were caused by a $6 spark plug. Mine were E3s with only 40k on them. This is the second time E3s have given me trouble - my HHR also exhibited misfires on E3s - either way, GM/ACDelco iridiums went in their place. Two days, 150 miles, no issues.

 

[rbstahoe]

Intermittent Stabilitrak issue

I just want to add my experience to the mix:

I have experienced the following with my 2007 Yukon SLT:
Stabilitrak OFF light on
Service Stabilitrak notification
Service Traction Control notification
Check Engine light on
Hard shift from 1st to 2nd gear

This situation has occurred 3 or 4 times over the last 2 years. It has only occurred after a long period of coasting downhill (approx. 6 miles) without using the accelerator. Each time, the above listed items occur. The Stabilitrak and Traction Control warnings will remain for one or two driving periods (turn vehicle off, let sit overnight, then drive again for a short time) then disappear, along with the hard shift, while the check engine light will remain on for an additional off, sit, drive cycle and then disappear.

I haven't had it in for service because the problem resolves itself before I can get to a dealer.
Fortunately for me this issue is very infrequent and clears up pretty quickly. It seems that if I use the gas pedal, at least once in a while, while coasting I can avoid the problem.

This probably doesn't help anyone but I wanted to add my experience to the long list. Fortunately for me this is the only issue I have had to deal with during the 3.5 years and 30k miles (110k total mileage) I have owned my Yukon. I have been very happy with the vehicle.

 

[93sc300.]

So I can add to this thread. I had this problem the other day with the "service stabilitrack.. service Traction Control", tranny wouldn't shift out of probably 4th gear at all. I disconnected the battery and it reset so I did some research and replaced the Throttle Position Sensor which was 58 bucks. The error popped up again 2 days later but I didn't have the tranny or accel issues. The CEL stayed on. After more research, I found that people had up to 40% alcohol in their gas when the problem started. I noticed I put gas at a different gas station so I ran the gas out of the tank, put gas at a regular station and right when I turned my vehicle on, the CEL was gone. No issues since. its only been a couple days but I will keep this thread updated. Im changing my plugs just in case so I can rule those out if the gas was bad. Hoping this works. Unfortunately, both the instances were at night so I didn't get the codes pulled. Im thinking bad gas is the culprit at this point.

 

[BanditHoe]

Yours sounds related to the E85 sensor. I wouldn't say it's common, but I've seen it before. The sensor that adjusts the AFR based on alcohol content sometimes gets hung, especially if it isn't used very often. A reset or reflash will usually reset the sensor, like you did.

 

[Bullypits]

Unbelievable I have the same issue rt now.. Service lights come on at a stop then as I take off a hard shift from 1st to 2nd and then its back to normal.. Wat is it??? Any help plz!! All so get a check engine light come on some times that sounds like a miss fire..

 

[kait pratt]

For months now my 2010 chev tahoe has been back and fourth to dealer with end result "Sorry Mrs. Pratt we weren't able to locate the problem bring it back when the lights come back on"

Randomly the "service suspension" light comes on and the speedometer acts erratically causing harder shifting. sometimes the check engine light comes on also. Will drive car for 20+ mins or so and it goes back to normal or I shut it off and it sits for a while and get back in and all services lights go off. Sometimes it says service suspension, traction control off, park assist off and service stabiltrack . I notice it happens more when there is moisture in the air. It is so aggregating that the GM dealer cant come up with a solution. They replaced the control module which didn't fix anything....

has anyone been able to get a similar problem fixed!!!

 

[broken08]

Mine started too. 2007 Yukon xl Denali 100k. No answers yet. Any more solutions? If you add up all the different things people have had to do, it sounds like just about every drive train part has been replaced with and without success. I might return this thing to the dealer I just bought it from while I can.

 

[retiredsparky]

The GM vehicles seem to have a (for lack of a better word) "buggy" or unreliable control system. I suspect there are too many lines of code with too many patches applied over the years to solve various problems. This is the problem with Microsoft applications as well.

Replacing the battery if it has been in the vehicle for some years sometimes fixes some of these issues. I have repaired several vehicles by replacing an older battery. In each case the batteries tested OK. The unusual symptoms totally went away. I believe that older batteries may create electrical noise in the vehicle, kind of like static on a radio. This is not to say that it will always work!

 

[puckhead]

Same issue here. Hard shift when coasting etc. I took it in and had the motor mounts replaced, they were bad. I think it helped a bit but I still have the thunk. Don't know what to do next. Wife is pregnant and I don't want it to break down with her in it.