How to Check the Valve on the Sump Pump of a Dishwasher

Cut off the electricity to the dishwasher at the circuit breaker.

Remove the screws on the edges of the bottom plate or grille. Pull down on the part to disengage it from the appliance. Set aside the plate or grille. Now you can see the sump pump underneath the dishwasher, typically near the center. The valve on the pump is connected to the drain hose, which extends through the counter closest to the sink plumbing where the hose taps into the main drain pipe.

Blot an old towel under the valve to check for leakage. Pat the valve with the towel, as well, to determine if water may be seeping through cracks or crevices, indicating internal damage with the pump valve.

Squeeze the metal band around the drain hose where it attaches to the pump valve, using pliers. Pull off the hose and hold it over the folded towel to catch any water in the line.

Poke the end of the screwdriver gently into the outlet on the valve as well as the drain hose to check for obstructions. Removed any blockage and reattach the hose to the valve, using the pliers to squeeze the hose clamp. If the hose and valve appear to be clear, continue troubleshooting.

Remove the two wires from the solenoid attached to the sump pump. Each wire pulls straight off using the Y-shaped connector on the end.

Test the solenoid with a multimeter dialed to the ohms setting. Hold each test probe against the terminals on the solenoid. If the display on the multimeter swings into the infinity range, the sump pump assembly is broken and must be replaced for the dishwasher to drain properly.