Power Steering Light On problems of the 2013 GMC Acadia

On multiple occasions now, my car has flashed "traction control off", "engine power is reduced", "service traction control", "service stabilitrak" while in motion at various speeds and has occurred most recently just prior to a curve that caused me to drive into the opposite lane because the engine shuts down causing no control in the steering when these lights come on. When the car is at a complete stop, it is then put into park and the key is turned to the off position and has had no consistency of if it will restart or not. If the traction control symbol is still on the display, it will not restart. It has been into the gm dealer it was purchased from with scheduled evaluation of the problem and they state there is not a problem with the vehicle and no codes stored in the system for them to evaluate this problem. The malfunction indicator lamp symbol will stay on or go off on its own at no specific rate. This is a huge safety concern that has caused my vehicle to stop unexpectedly while driving 55mph down a state route and limits steering ability when this failure occurs causing my vehicle to go into the oposite lane on the road. I did record the dash indicator lights after the vehice was at a complete stop partially on the road while still in drive for the dealership service department to view these on the display and I also have the copy of the service department paper that describes there were no repairs completed due to no failure during scheduled appointment on 2/9/17. The malfunction indicator lamp (check engine light) was still on the display when vehicle dropped off in the evening before the scheduled service. Upon pickup on 2/11/17 there were no indicator lights on the display. I am unable to put the mph or estimated miles in the alloted space on last incident on 2/15/17 so am adding here; I was driving about 35mph and there was about 98,170 miles.