After replacing door handle, I find the “door open” light goes on when the door is closed and vice versa. I’ve reversed the leads on the microswitch attached to the latch but it makes no difference.
Here are your parts
Replacement parts for WHIRLPOOL KUDV24SEBL1 | AppliancePartsPros.com
Here is the tech sheet
https://www.servicematters.com/docs/wiring/Tech%20Sheet%20-%209743409.pdf
Looks like a problem with the keypad (VFD) or the control boards interface IC.
Remove the ribbon cable at the control board and reconnect it.
If it is still broken
Visually check the connectors and the ribbon cable (hairline cracks across tracks). A magnifying glass comes in handy here.
If all OK try cleaning the connectors with electronics contact cleaner or isopropyl alcohol and a tooth brush. Be sure to let all the solvent evaporate before reconnecting.
If it still has the error check the keypad with a meter.
Note I could not find what is actually being checked to give this error but perhaps I just missed it.
Also according to the wiring diagram opening the door should kill power to the unit.