NHTSA Complaint #11562725 — 2017 CADILLAC XT5

Message Displayed on 2017 Cadillac XT-5 "Steering Assist is Reduced - Drive With Care". No check engine light, and no apparent loss of steering. Noted that Temperature Gauge and Air Conditioning ceased to work. Suspiciously, a 2019 Cadillac XT-5 that I also own, the identical displayed message came on, with identical same mechanical issue, and just learned that an acquaintance with a newer Chevy Blazer just experienced the identical issue also. All vehicles are equipped with OnStar. Coincidence, OR any possibility that GM or OnStar computers have been hacked into, as OnStar has ability to control various functions of vehicles. To correct the issue (possibly only temporary) was to remove the negative battery cable for a short time, and reattach.