Just bought this baby used and can't get past the C4 error. Thought I solved it several times. Steps I've taken that didn't work:
* Used a bucket to gravitationally empty the full tub scores of times. So the tubing isn't blocked.
* Removed and separated the motor mechanism. Spins fine and runs during the Reset cycle. Just doesn't drain the water in the tub.
* Dis- and re-assembled the Drain Solenoid. Straight bar on sensor switch wasn't pressing the switch when solenoid activated. Bent until it does. Solenoid fires and switch is pressed now. I've seen the solenoid fire and withdraw. Gate valve arm opens and closes as best I can tell.
* Pulled and de-gooked the sump cover and tank below. Thought that pound of grease would fix it. No such luck.
* Disassembled the Water Valve. No visible problems. Unwired Ohm reading of 1.1 (digital Ohm meter set at 200k). Seems okay to me. (I'm no electrician, though, so I'm here asking ya'll).
* Disassembled the float switch. Cleaned out the gook in case it wasn't floating. F-1 Test Cycle still overflows at water fill and fires the C4 error.
* Pulled the Float Switch and checked it out. Still clicks nicely. Ohm meter readings jump around from 0 to 30 when the switch is depressed, and resolve to about 0 when the switch is unpressed.

I'm about out of clues here. The dishwasher panel and all of the major functions seem fine, I just can't get it to drain the darn tub. It fills up and then overflows every single time. I can't get a drop out of the drain unless I lower it to suction out the water. I'm about to call it quits - but I know I'm very close to success.

Can anyone help me? Standing by...

~Mark->