Error i 30 can also be caused by any open circuit in the control wiring for the float level switch circuit located in the bottom of the dishwasher. I had this problem and found a faulty - loose crimp link on a switch. I traced the wiring which also incorparates the cold water supply hose solenoid. I checked for continuaty of the soleniod coil and there it was . The coil was open and this was the cause of the fault. I replaced the supply hose assembly and the dishwasher works perfectly. CAUTION. obviously disconnect the power when working or testing the dishwasher. It might be a little easier for me to find as I am a qualified electrician and it was pretty basic to me although a cicuit diagram would of helped.
sparky
April 2018