Disconnect the power to the unit at the power supply or breaker box.
Put on rubber gloves and clear any clogs present in the kitchen sink drain with a plunger. Reach into the back of the unit and clear any clogs in the dishwasher drain plug opening.
Remove the garbage disposal drain plug, if applicable. Remove the metal air gap cover on top of the kitchen sink. Remove the plastic cap and clear any debris clogging the air gap.
Straighten any kinks in the dishwasher drain hose. Raise the drain loop slightly if your system does not include an air gap.
Pour 1 cup vinegar into the bottom of the unit and run the hottest, longest cycle to de-scale the piping and drain.
Use less dishwasher detergent to prevent excessive frothing or foaming that compromises the drainage system.