Check the door latch sensor with a multimeter. Confirmed that the latch sensor was working properly. Tried to use the status LED on the main board to determine the problem, but LED would never light up. Looked at forum posts from other people with the same problem. They reported that a door sensor issue plus non-working status LED indicated a mainboard failure and replacing the mainboard resolved the problem. I ordered the replacement mainboard and swapped it out. Dishwasher worked immediately.