If, after your dishwasher is through cycling, you open the door and find your dishes are not clean, it could be that you just didn’t clean off the cooked on food enough or you may have placed dishes, glasses and cook wear in the dishwasher rack incorrectly. If you did everything right then you probably will need to troubleshoot some of the other causes.
A dishwasher has a water inlet valve that regulates the flow of water into your dishwasher. Too much water will cause the water to run out of the dishwasher tub and too little water will leave your dishes dirty. You can check the water inlet valve by allowing water to run into the tub. The water level should be just below the float. Let your dishwasher run for a few minutes into the cycle and check the water level again. If you see there is less water in the tub, then the inlet valve may be letting water drain before dishes are clean. Should this be the problem, you can replace the water valve or call a reputable appliance repair person.
If the water inlet valve was not the problem it could possibly be the dishwasher drain valve has failed. When the drain valve fails it causes the used, dirty water to recycle over your dishes, yuk. Not all dishwashers have drain valves. Check yours by unplugging the dishwasher or turn off the power at your breaker box. The panel below the dishwasher door needs to be opened and you can then see the motor, pump and drains.

Dishwasher Water Inlet Valve
If there are two or three wires coming from the motor then you know your dishwasher has a drain valve. If there is no drain valve present then your dishwasher reverses the main motor to empty the dirty water from the tub. Locate the drain valve close to the water hose underneath the tub. To determine that the drain valve is operating correctly simply push on the drain’s gate arm. While doing this, if you notice one of the springs on the gate arm looks asthough it is not operating correctly, replace it.
You can test the wires on the solenoid with a multi-tester. Disconnect the solenoid wires and using the multi-tester determine that it reads 40 OHMS. If any other reading shows then the drain valves solenoid should be replaced because it is defective.
Dishwashers have spray arms and some have a tower in the middle of the tub which pops up to dispense water. Either of these, if not operating correctly, can cause your dishes to remain dirty. There are small holes in the washer arms that can clog with particles of food. If you have hard water, lime scale can also clog up the holes. Clean out the holes and make certain the arms turn freely. If your dishwasher has a tower make certain it is not blocked by your

Dishwasher Spray Arm
dishes when loading your dishwasher, it needs to be able to pop up and spray water freely.
You should also check the soap dispenser to determine that nothing is blocking it from opening during the wash cycle. There is a timer motor that opens the dispenser door and that could be bad. If the door doesn’t open after going through several cycles then it’s time to replace the timer motor and its solenoid. A rinse aid dispenser solenoid may also have to be replaced at the same time.
Some of the general repair tips presented above may also apply for,
Maytag, GE, Frigidaire, Bosch or Kenmore dishwasher repairs, as well as many other makes and models of dishwashers.
You may prefer to call a qualified appliance repair person to do this work.