First I watched several repair videos on YouTube for this dishwasher [DW] and read some repair forums. [Note: other similar KitchenAid and Whirlpool models operate similarly].
My problem was a stuck closed membrane switch [button] the front Control Panel [CP]. When pressing "Start/Resume" the Electronic Control Board [ECB] wouldn't run wash but instead just flashed the LEDs.
A double-check is to [1] Unplug the DW [2] access the ECB in the door [3] partially lift out the ECB [4] disconnect the CP multicolored ribbon cable [5] replace the ECB [5] Put everything lightly back together [] close the door, and [] plugin the DW.
If you have a [probably] good ECB, it detects that there is no CP connected and simply runs a "Drain" cycle, then stops, [approx 2 minutes]. This is a fairly strong indicator that the ECB is good but the CP has a stuck "closed" button. [The ECB cannot detect a stuck "open" button because that is the normal state. But also, a "stuck open" button is very unlikely.]
We also cleaned out the Filter Assembly, Sump Housing, Chopper Cover, and Chopper. This is worth doing too at this time but is a bigger and more awkward job than simply replacing the CP.
You'll need Torx screwdriver bits to do this job.
Good Luck!
Video for replacing the CP:
https://www.youtube.com/watch?v=bebKZZQILH4