Add 1 quart of water to the bottom of the tub in your KitchenAid dishwasher if you hear a squealing or rattling pump noise. This noise will occur if the dishwasher is new or hasn't been used in a while and occurs when there is not enough water in the device. Adding water will lubricate and quiet the pump seals.
Rearrange dishes inside the dishwasher to get rid of rhythmic knocking. This sound is often a result of the spray arm bumping into objects inside the dishwasher. Make sure the spray arm can't hit any tall dishes.
Remove all dishware from the KitchenAid dishwasher if you hear a rattling noise, and run the dishwasher again, empty. If the noise is still present it is likely caused by debris lodged in the pump. Call KitchenAid customer service or a professional appliance repair service to clean the pump. If the noise doesn't occur when the dishwasher is empty, water is likely pushing lighter dishware out of the racks during the wash cycle. Make sure all dishware is in the racks securely.
Call a plumber to install an anti-hammer device if you hear pipes rattling or banging, or a booming noise. These are often caused by a household plumbing issue.