Dishwasher has buzzing noise when running - KitchenAid Architect® KUDT03FT 24 in Builtin Dishwasher

Mine does this too. I think it has something to do with a self-cleaning cycle where the food chopper (miniature garbage disposal blade) runs to chop up debris. Mind runs this way every 30 washes or so (every 4-6 weeks), perhaps in response to water turbidity (soil sensing)

This may be the same problem we had, although the noise was more like grinding instead of buzzing. The motor shaft drives the pump and water can easily enter the motor bearing. This rusts the bearing which causes noise and slows down the motor, making the wash action even weaker than normal. Mfr claims there is no design issue but guess what? They have added a 2 cent barrier to prevent this problem on the replacement part. You cant buy just the motor, you get the entire motor/pump/disposal assembly and its pretty expensive, but basically you are replacing most of the working parts so the machine should be like new if the washing arms are not plugged (which they usually are).