Customer Questions and Answers for Dishwasher Control Unit by Bosch

Hello Xuesheng, This is either going to be caused by a low water fill of a lack of water circulation. You should fill the unit and make sure there is water visible in the bottom and check the filters to be sure none are clogged. There is a fine filter that should be cleaned out periodically or water circulation will be hampered. If these are clear, make sure the gaskets at the feed tube that supplies water for the center spray arm are present and intact. You may need to replace the water valve in the case of a low water fill and you may need to disassemble the pump assembly to verify the impeller is operating properly.