I also received this message on my 2022.5 GMC 1500 with the 2.7. I know for certain my trailer is not over gross with the weight of the truck. I didn’t receive this type of message until a recent technical update was done. I’m assuming when I last took my truck in for a recall fix. At that point they did an update to the trailer brake that previously was not working. I typically get the code when accelerating, such as from a stop sign at an incline or when the wind is dragging, or when on the interstate even at lower speeds.
I am very concerned this is to void a future warranty claim. The very reason I purchase new vehicles.
I certainly follow the manufacturer guidelines such as higher octane gasoline but I’m definitely concerned that GM is looking for an excuse.