OK… You have a Whirlpool Duet, Kenmore Elite or Maytag Epic front load washer and you are now experiencing the F35 and SUD error codes. Take a deep breath, relax and read along because I will explain how you can determine if the CCU (control unit) or the analog pressure switch (APS) is causing your issue so you can prevent an expensive service call.
Let’s learn what happens when you start your washer. First, after some checks and dispenser adjustments the CCU will open the water valve(s) and let a known amount of water in and then stop. It is the APS’s function to give a voltage signal that represents the water level in your washer. For example, with the tub empty the W10415587 APS will output about .38 VDC and after the first fill it will output about .7 VDC with no clothes in the washer. Note: If you have clothes in there the output voltage will be less because the clothes will absorb some of the water so this also gives the washer an idea of how large your “load” is.
There is a hose that originates on the bottom of the large tub that goes up to the APS and when the water level rises it pushes air up the hose and into the pressure sensor IC inside the APS. The pressure sensor IC then senses the pressure and outputs a representative voltage that the CCU can measure to determine the water level. Note: Earlier washer models used a simple pressure switch which had only one or two snap over points. The advantage of the APS is that it gives an accurate output based on the water level.
So… If the APS is outputting a lower voltage (or higher) than what the CCU expects then it will turn on the F35 and SUD errors and the machine will attempt to pump out any remaining water. From my experience… early on you will be able to “reset” machine by unplugging it for 20 seconds. Plug it back in and try again. The errors will probably become more frequent and eventually your smelly clothes pile will grow because you will not be able to start the machine!
There are videos available to help you determine if the CCU or the APS is causing you grief. If it is the CCU then there is a repair kit with step by step DVD that works 99% of the time where you replace some components on the CCU circuit board.
One video shows how to check the APS output voltage while in the machine and see what the voltage signal is using a volt meter where another helpful video shows how to test the APS with a 5 VDC power supply on a bench. If you determine that your W10415587 APS has failed there is a repair kit with DVD for that, too!
I recommend that you get started watching the videos so you can determine if the CCU or the APS is the culprit and get your machine back up and running!