I think I'd have someone in the TV engage the brake. Then I'd trace the wiring of the Prodigy and wiggle sections at the time to see if I could duplicate the error reading. It sounds like a wire/connection going bad but not quite broken, yet. The problem could be anywhere from the Prodigy to the TT brake so that could mean a lot of wire shaking.
A long story to explain my reasoning:
I use to own a 63 Chevy that I really loved but it would make me so mad because every time I made a righthand turn the motor would turn off. It would loose all power and the motor died. Frustrating in traffic. I would get out and with the motor running I'd wiggle the wires but I could not duplicate the problem. I even turned the wheel to the right but it only happened when I made the turn to the right while driving. I was going to do a tuneup and opened the distributor to do points. That is when I noticed the condenser wire had been pinched. Putting the test meter on that wire I had found the "loose connection". The insulation was solid but when I made the right turns the wire inside the insulation to the distributor would shift to a open/broken position. When stopped the wire would reconnect and work as it should. I replaced wire, saved car and my sanity. Something similar could be happening with wiring to your Prodigy and what looks to be good, isn't.
Beverly & Jim
1991 T-2363 Solaris