long story, over the last 1.5 years i would occassionally get a p1774 code (low coast brake solenoid), it would cause it to go into limp mode, if i turned it off and on, it would run fine...it went away for about 1 year then came back and did it more frequently.

i decided to take out the valve body/tcm and repair it, i replaced all the shift solenoids (the low coast brake solenoid was bad and wouldnt "click" when energized by car battery, I also took the tcm apart and checked for any breaks in continuity from the shift solenoid pins, all seemed to be in good order.

i put everything back together and now it wont ever leave limp mode, i cannot shift manually and it is throwing p1772 code.

people i bought the shift solenoids from say the transmission must be flashed...this doesnt seem correct since i didnt change the valve body or tcm, just the shift solenoids.

so i took the valve body back out, i dissassebled the tcm, and i found that the low coast brake solenoid wiring seems to lose continuity at the positive block... all the others have continuity with a certain amount of resistance...

Many TCMs have memory that decays when power is lost. As well, being a solid state part in places means that simple use of a voltmeter can provide enough voltage to blow one out.