With the hose off, look into the open drain port on the dishwasher.
Pull up on the center of the bottom spray arm. It usually pops off. Set it aside. If it doesn’t pop, look for a small nut or a clip.
While you have the machine pulled out, check the drain hose routing. If the hose droops down and then up to the disposal, dirty sink water flows back into your dishwasher. how to clean out a dishwasher drain exclusive
Exclusive Installation Standard: The drain hose must go UP to the underside of the countertop (creating a "high loop") before coming DOWN to the disposal. Secure this loop with a zip tie.
No high loop = Dirty water re-enters your dishwasher every time you run the sink. With the hose off, look into the open
Now that the mechanical debris is gone, we kill the biology.
Reattach the drain hose and the air gap. Push the dishwasher back into place (leave the kickplate off until you test it). Reattach the drain hose and the air gap
Pour 2 cups of baking soda directly into the sump pit (where the filter goes). Then, fill the filter basket with 4 cups of white vinegar. It will fizz violently. Let it sit for 20 minutes. This neutralizes odors and dissolves soap scum.