Eric R. for Model Number wfw9400sw03 The tech sheet says to be sure the wires are good and the connections are good at the ccu and the mcu. Then to unplug the m13? plug on the ccu. When I did that the code F78 no longer was displayed but a communication failure error code came up. I think the mcu is drawing down the communication link and stopping the washer from doing anything. The first code told me "No Heart Beat" for the ccu. after unplugging the wires from the mcu everything from the user interface control seemed to work (except the motor and pump) but the mcu was unplugged. During the drain/spin cycle after a couple minutes I got a communication failure code again. Seems normal. So is there a way to test the mcu?
Answer Hello Eric. If the code went away and the CCU is good, then according to the tech sheet, the MCU WP8183196 is bad and will need to be replaced. If the drum is rotating, you need to replace the user interface. Hope this helps. Read More... Answered by AppliancePartsPros.com | Wednesday, October 5, 2011