Yesterday I was driving back from the country and half way home I hade the service 4x4 light come on my display and may trailer brake control message come up saying "trailer brake disconnected".?? I wasn't hauling a trailer. This just came up out of nowhere. both faults came on at the same time. Not sure what would cause this. When i got home, I turned off the ignition and started the truck again and the messages where gone. Does anybody know what would cause this?