[laverdur]

I had this error and a few others, depending on what was happening at the moment. It took me a lot of troubleshooting to finally determine that the brake wires inside the axle tubes were chaffed and the conductors were shorting to the metal axle tube. Ford trucks send a health and status pulse to the trailer brakes every 4-5 seconds. If a short exists at that moment you will get a fault. The short will come and go as the axle bounces down the road so the fault is very unpredictable. Sitting still, if the wire is not shorted, the brakes test perfectly. I don't want to tell you haw many nights I lost sleep over this problem. Solution - cut the wires going into the axle. Buy a small spool of wire and put new wires on the outside of the axle tube. I went to Home Depot and bought a strip of plastic Wiremold long enough to cover the wires as they traverse the axle. A few zip ties later and you are good to go. No errors since making that fix.