Whirlpool Dishwasher Error Code 6-4

Code 6-4 means the control board is detecting the float switch in an open, or triggered, state, indicating the overfill protection system thinks the tub is at an unsafe water level. This can happen because something is physically holding the float up, the dishwasher is not sitting level, or the float switch itself has failed. The dishwasher will block water fill until the condition is cleared.

The dishwasher will not fill with water while code 6-4 is active, so running a cycle is not possible in this state. The code is a safety lockout designed to prevent actual overflow. Do not attempt to bypass the float switch to force the machine to run, as this removes the only protection against the tub overfilling and flooding the floor.

If the float moves freely and the code comes back, the float switch itself is the next suspect. Remove the lower access panel and disconnect the wiring harness from the float switch, then test the switch with a multimeter set to continuity. With the float in the down position the switch should show continuity; if it reads open, the switch has failed and needs replacement. Also check the wire harness connector for corrosion or a loose pin, which can mimic a failed switch.

Start by opening the door and locating the float, which is a small plastic cap usually found in the front corner of the tub floor. Lift and release it by hand to confirm it moves freely and you hear a click from the switch contacts when it drops. Remove any debris lodged underneath it. Next, use a level on the dishwasher floor and adjust the front leveling legs if the unit is not sitting flat. If the float is clear and the machine is level but the code returns, test the float switch with a multimeter and replace it if it reads open with the float in the down position.

If the cause is debris under the float or an unlevel installation, the fix costs nothing. A replacement float switch assembly for a Whirlpool dishwasher typically costs between $15 and $40 for the part. If you replace it yourself, that is the total cost. A technician visit adds $100 to $200 in labor depending on your area, making professional repair for a simple switch replacement a $120 to $240 job in most cases.