I have seen this message a few times with my 2015 Silverado. I have replaced a couple sensors but also found that other things can cause that message to appear. One word of caution, when it comes on, you lose your trailer brakes...
First, I was told by the dealer, never plug in the trailer with the truck running, turn the truck off before you plug in. Then, if you are still getting the message, try dialectric grease in the plug, the corrosion, or dirt, etc, can cause a bad connection, the dialectric grease helps. I have 2 trailers about the same age, with one I get this error more than the other, but usually stopping, turning the truck off, then plugging in getting a better seal, then it stops for the duration of the trip. If it continues, or you get that warning without a trailer, you have a bad sensor or something else. I have had to stop and unplug, re-plug more than once on a trip to get it to work correctly. The computer that causes that message is very sensitive. I have read other threads where people think they fixed the error permanently but my experience is that you can stop it for a while, but it comes back. Usually it is not a sensor but something with the connection between the truck and the trailer.
