Kitchen Aid KUD1021 Dishwasher - Buzzing Noise

[personal champ]

We have a Kitchen Aid KUD1021 dishwasher that is approximately a year and a half old. Tonight it started making a buzzing noise during the cycle, which has never happened before.

I can't find the manual (bad appliance buyer!) so I can't reference that. I tried finding it online with no luck. I'm not sure if there is something stuck in the food chopper, which I don't know where it is since there is no manual, or if it could be a motor problem.

Any advice would be greatly appreciated!

Model Number: KUD1021RWH1