Never mind. Figured it out. The service diagnostics sheet had a typo. It said "Press and 3 keys in the sequence". I thought is was purposely not telling you the keys so you would need a repairman to "unlock".
What it meant "Press ANY 3 keys in the sequence 1-2-3-1-2-3-1-2-3 with no more than one second between key presses".
This ran diagnostics (which I was still struggling to interpret) and then did a small run of the different cycles. After that, I ran a 1 hour wash and everything worked. Not sure what happened but perhaps analogous to rebooting a computer. Whatever the reason, we are back in business and don't have to do an emergency 4th of July dishwasher replacement!