Change Upper Rack Loading
KitchenAid states that its dishwashers' upper rack is "designed for cups, glasses and smaller items." Avoid putting larger items on the upper rack. Most larger items, such as pots and pans, tend to have more food scraps on them compared to cups and glasses. Larger items need a more powerful water stream, which the upper rack does not receive. If you're already limiting the upper rack to smaller items, consider how you're stacking them. Every item should have enough room for the water streams to reach in and around it. For example, do not lay cooking utensils on the rack and position glasses over them, as this greatly diminishes the amount of water that can get into the glass.
Avoid Lower Rack Obstructions
Even a perfectly loaded upper rack may not get clean because of the lower dishwasher rack. Check that lower rack items, especially large pots, are not fully blocking the water jets from reaching other dishwasher areas. Some KitchenAid models have a water jet that rises from the center of the lower rack during the cycle. Avoid obstructing that area, denoted by a cutout in the rack, when loading the lower rack.
Check the Water Pressure
KitchenAid recommends checking your water pressure if your top-rack dishes emerge dirty after a wash cycle. Water pressure for optimal cleaning should be 20 to 120 psi, according to KitchenAid. Follow KitchenAid's recommendations for checking your water pressure. Position a 1-quart container under the faucet nearest to the dishwasher and turn the faucet on all the way. Time how long it takes to fill the container. Anything longer than nine seconds indicates a lower than optimal water pressure for cleaning upper-rack dishes. Talk with a plumber about boosting your home's water pressure.
Clean the Filter
Some KitchenAid dishwashers have a filter system that keeps food pieces out of the pump. Over time, the filters can get coated with food waste, preventing the dishwasher from operating properly. Dirty dishes are one sign that the filters need cleaning. Depending on how often you run the dishwasher, KitchenAid recommends cleaning the filters weekly to every two months. Remove the lower rack and turn the upper filter, which looks like a small canister, counterclockwise with a one-quarter turn. Pull it straight out. Pull the lower filter, which looks like a small, flat screen, up and out. Rinse both with water until clean and replace, positioning the lower filter first, then the upper filter.
Search for Clogs
If your loading is impeccable, your water pressure ideal and your filters spotless, check your KitchenAid dishwater for water jet clogs. The spray holes in the water jets can get clogged with food debris, reducing their power and ability to reach the upper rack. Use a toothpick to clean out each hole of the water jets.