Or, cat eyes re-visited. I had this problem before, just sitting in the shop. The transmission shift pad starts beeping and showing the cat eyes. It has been sitting for a couple of weeks. Shows no codes. Since one of the suggested causes was low voltage I hooked up a battery charger to the coach batteries, even though they tested over 12 volts. That solved the problem. Took the charger off for a day and the problem returned. Charger on again, problem disappears. Batteries are new but I'm suspecting a problem with them, but the other question becomes, why is the transmission caring what the voltage is when it's shut off? I'm guessing there must be a constant drain on the batteries to maintain a computer or something in the transmission?
Gayland,
Check and clean all the grounds related to the coach and starting batteries.
I've been off on a trip. I had the batteries checked while I was gone. One of them was bad, 5 month old from Napa. They gave me a new one, haven't had any more problems so far, at least not with the coach batteries.