Whirlpool Dishwasher-Model # WDT720PADM2. Customer complaint- dishwasher turns on and runs for a few minutes then stops and flashes lights. Service performed- Specialist removed and replaced the pump & motor (Wpw10671941/pump&motor). had a little trouble retesting the unit. Moved plug to good outlet and found no codes stored. Ran unit and sink began to fill with dirty water. Customer has a clogged drain. Also found customer did not have air gap. Recommended installing air gap. Service completed.