The dishwasher fills and stops. A slight hum is heard for approximately two minutes then stops. There is a rotating pattern of lights visible in the display window that runs continuously without anything happening. I hit the cancel/drain button after 20 minutes, it drained and shut off. I ran diagnostics which did not indicate any problem. I cleaned the chopper and separation screen which had minimal debris. Chopper blade did not rotate. Check valve appeared normal, no wear/tear. Overflow protection float and fill valve are operable. Is the wash motor at fault/should i replace it? Are there any other diagnostic steps I can take to isolate the problem? Thanks for your help.