I have been having a very similar problem on my g/f 2002 P5.
At first it started throwing a "camshaft sensor electrical" then started with P0773 "Shift solenoid E electrical"
I have traced through the circuit from solenoid E to the PCM per the workshop manual and it all checked out.
So now 10 days later P0768 "Shift solenoid D electrical" pops up.
This seems to cause a shifting problem sometimes it downshifts 1 or 2 and the time I tested everything it was consistently having problems just cruise it would start trying to shift.
So have you had any luck with figuring out the problem if it wasn't just to replace the solenoid?