Did you reset the 'puter? Mine threw that code about 2-3 years ago, not sure under what condition, cleared it and it has not returned, yet. My trans is like yours, shifts fine and has clean, clear fluid. Here is some decent background info on good ol' p0773: https://www.yourmechanic.com/articl...ift-solenoid-e-electrical-by-valerie-johnston
Yes it was a simple repair. I took it to naperville toyota and was quoted 750.00 to fix the problem I said NO. Watched a few videos on youtube...ordered new solenoid for 20 bucks popped it in and has worked like new for the past 7 years.