Stabilitrak, reduced power assist, and service trailer brakes

[Mike431987]

Was driving yesterday and all of a sudden the stablitrak service light came on and steering power assist off as well as service trailer brake. Light went away after driving a Few miles. Parked it and started it back up and came back on again. I noticed the first time it happened after turned left but the second time I was going straight. Sometimes it goes off and comes right back. Truck is nearly undriveable because it pulls the steering wheel when it comes on.   Besides the grounds under the dash for g218. Anyone have any ideas? Not alot of info on this.  I would assume if it was steering sensor or wheel speed sensor it would throw abs light to. Thanks in advance 

Edited December 19, 2021 by Mike431987
Added

[Sal2018 z71]

Hello did you ever figure it out? I’m having the same issues on my 2018 Silverado 1500

[2018GMC]

21 hours ago, Sal2018 z71 said:

Hello did you ever figure it out? I’m having the same issues on my 2018 Silverado 1500

G218 ground shouldn't be an issue on a 2018. I would occasionally get service stabillitrack on startup but thats it. Check and clean all your grounds, especially the engine ground to body.
There are 3 frame grounds:
1. under driver seat on frame 
2. behind front passenger wheel well
3. on top of spare tire by trailer tow package.

Your negative battery cable may have high resistance and need replaced. Dealer replaced mine and it didn't really change anything but they said it was out of spec for resistance.

Here is the official Technical Service Bulletin TSB
18-NA-161 1..7 (nhtsa.gov)