Over time, the detergent you use to make the detergent/water solution you mix for the detergent tank may separate from the water. This congealed detergent may accumulate in the tank, hose and wand. Small particles that come from or through your water lines may lodge in the hose and wand.
Back flush to wash congealed detergent and accumulated particulate out of the hoses and wand and into the detergent tank where it can be removed. Your Dishmaster will work best if you routinely perform the back flush procedure. Make it a habit to take a few moments and back flush every time your tank runs empty and before refilling.
Are the M2000 or M70 hose connections made properly? Check the connections
If the back flush procedure does not correct the problem there may be particulate stuck in the needle valve or other components of the venturi assembly may be broken, worn or out of position. Refer to instructions for K0264 Needle Valve Repair Kit and SA0292 Venturi Assembly