The F35 error code indicates an analog pressure sensor error. The analog pressure sensor is the component that detects water level in the washer tub. This error can usually be cleared but it will occur again if the main control board still detects a problem with the signal from the analog pressure sensor. This error code can be caused by a problem with the air pressure tube between the bottom of the washer tub and the analog pressure sensor. If you are able to
unplug the washer
and check this air pressure tube, you may be able to resolve this problem. The analog pressure sensor can be accessed by pulling off the top panel of your washer. Remove the screws at the very back of the top panel and then pull it back slightly and then up and off of the washer. The analog pressure sensor is Key 38 in the first image below. With the washer unplugged, check the connection of the air pressure tube to this component. Check the entire air tube down to its connection to the bottom of the washer tub. You will likely need to remove the back panel of the washer to check the entire air pressure tube. If you find a kink, tear, hose or loose connection in the air pressure tube, then this is the likely cause of your F35 error code. If the air pressure tube appears to be okay, then you will likely need to replace the analog pressure sensor. If the problem still exists after replacing this component, then the main electronic control board for the washer will need to be replaced. If you are not completely confident in your technical ability to safely access and check these components, I recommend calling a service technician to diagnose and repair the washer.
This information was based on the general description of the washer model that you provided (Kenmore Elite front load washer). There are several different models of this washer. I am not aware of other uses of the F35 code on the various models. If you intend to diagnose and repair this problem yourself, I recommend resubmitting your question with the full model number of your Kenmore washer so that we can verify this technical information using your model number.