[got9lbs]

I keep getting a TBC Fault everyday when I start my truck for the last month or more. It started off just happening at random but in the last 3 weeks it happens everytime I start and drive. THIS ALL HAPPENS WHEN THERE IS NO TRAILER ATTACHED. When I hook up the trailer it still beeps but the brakes apperar to work, when I use the manual slide they work great. It is an 2006 f250 6.0 diesel 4x4 if that makes a difference. Please help I have spent the last 3 hours reading post from my search on here and other sites and I cannot seem to put my finger on the exact solution. I have seen master cylinder needs to be replaced, the controller is bad, a bad ground or a short in the harness. Im confused please let me know what to look for!