Whirlpool WDP540HAMZ dishwasher does not clean dishes

The checks in more detail

Put the dirtiest items facing the center, keep dishes apart and do not let large items block the arms, and do not overload. Use the Boost option for baked-on soil, and a stronger cycle such as Pots and Pans rather than a light one. Do not rinse plates to spotless; scraping is enough, since the sensor and the detergent need some soil to work with. Use fresh detergent in the right amount, in the dispenser, and rinse aid, particularly in hard water. The WDP540 has a plastic tub in this tier, which keeps less heat, so drying is weaker, though it does not affect cleaning. Check the water. It should be hot at the tap, and the inlet screen should be clear for a good fill.

A leaking door or a failing pump reduces the water in the wash. If the dishes still come out dirty, run an empty cycle with a dishwasher cleaner, then try again. If one area is always dirty, such as the back of the lower rack, check for a blocked arm or a poorly placed item. If the problem persists with a clean filter, free arms, proper loading and fresh detergent, the circulation pump or a seal may need service; contact Whirlpool with the model and serial number. Clean the filter monthly. On the WDP540HAMZ, the top rack carries the main spray arm and the bottom rack a lower arm, and both rely on the water pressure from the pump;

if the wash is poor in one rack only, look at the arm for that rack. Check that the arms are firmly seated and that the fixings are tight, since a loose arm sprays unevenly. The dishwasher has a soil sensor that adjusts the cycle, and if the detergent is weak or the sensor is covered by film, the cycle can be too short for the load. Clean the sensor area at the bottom of the tub. Whirlpool's dishwashers do not need pre-rinsing, but you should scrape off large scraps. Use a dishwasher cleaner every month, and use the hottest water the dishwasher is rated for.