water in and or around the mcu is a major problem if the water has effected any component in the mcu. I dont have specific details or instructions to offer, but with a good tech sheet or wiring diagram you should be able to test voltage from the mcu during the normal wash and look for chsanges or anything not the way it should be. It is very possible that water in the mcu could cause damage to the main control board. Sometimes you replace one and not long after that tou have to replace the other. Are there any signs of actual water damage or burn marks on the board? Water stains? Im on my phone so i cant pull up manuals or diagrams, but if everything is digital and electronically controlled, whatever is sending the signal to drain or stop draining or even advance to the next cycle is going to be the problem. Also depends if the motor and pump are one in the same or if they are seperate.
Sry if i didnt help u any