Mold in a dishwasher is not a pretty site and may also cause odor. I located a video and an excellent previous expert post that may help. I attached the links below. I would suggest adding the complete model number to help the expert provide the best answer possible. I hope this information helps.
This isn't a normal problem with dishwashers. On most models there will always be some water in the sump to keep the seals moist and prevent them from leaking. My first suggestion would be to use Vinegar to clean out the interior of the dishwasher. Select a cycle with hot water such as Pots and Pans or Sanitize and after it fills add a cup or two of Vinegar to the water. This should kill the mold. Repeat as needed.