No pressure during wash cycle

Model SHU43C02UC/17 fills and drains fine but during the wash and rinse cycle the water just dribbles out of the spray arms. I checked the water flow to the machine and found it to be fine. I removed the filter in the basin and made certain it was clean. I also removed the arms and checked for clogs, none were found. Remove cover of the impeller in the basin and checked for clogs and found nothing. What next? Regarding a Bosch built in dishwasher SHV46C03OC/14 The upper arm is not spinning. I have cleaned the unit by hand, filters, arms and with CLR (chlorine, rust and lime cleaner) as suggested by Bosch. The bottom dishes come clean but the top is not. I have checked the water level after it fills and it seems like it is only near the filter on the bottom. Is this normal water level because of the type of circulating system of this unit? Is this a water pressure problem? --and dur to what - the switch goin off early or the cir pump. I am reading too much about this machine on these blogs. I did notice that the detergent cup stays half filled. Is this due to the water not hitting it or the mineral deposits from our well water? Please help Thanks