So just read this post and same thing happened to me yesterday in my 2020 Silverado 3500 diesel while towing the boat and coming back from a trip to the keys. STRANGEST THING HAPPENS NEXT!! My brother in law who has identical truck as mine following right behind me has the exact same thing happen to his truck at the exact same time as mine. We both pulled over thinking GM just sent a signal to disable our trucks. After a couple of starts on and off it cleared and never did it again. Parking brake error, check engine light, turned off cruise and tow mode, reduced power and traction control light came on. How could this happen to two trucks at the same time unless it was sent over the air???