I went to google, searched for, Dish washer will not properly rinse dishes, leaves a white residue, It showed several possibilities, and I knew the dish washer pods I use are top brand, I went to Appliance Parts Pros.com, used their troubleshooting guide, where they have a list of what might be the cause, along with what the percentage of each is, i.e. I think that the circulation pump was around 60% possibility of being the issue, and the others were much lower, By Trade, I'm a mechanic, with over 35 years experience, so I do understand troubleshooting, no matter what it is, Here is my secret, lol! Before you purchase a part from APP.com, know this! You can reach out to them by Phone, Email, Chat before and even after your parts purchase, all though I would say start at before. That's why I'm confident in using APP.com, They back up what they sell.