If your Bosch dishwasher is overflowing, start with the most likely cause: a water inlet valve that is stuck open and keeps letting water in after the tub is full. This is a common reason a dishwasher overfills with water, especially if you notice water collecting in the bottom when the machine is off or dripping in with the door open. Next, check the main control board, since a shorted board can keep sending power to the water inlet valve when it should shut off. A cracked lower wash arm assembly can also make a Bosch dishwasher look like it is overflowing by spraying water out the bottom of the door. After that, consider whether the wrong detergent or too much detergent is causing oversudsing, then inspect the control board and the float switch, also called the safety float switch, which helps stop the fill cycle before water gets too high. If your Bosch dishwasher water level is too high, enter your model number on RepairClinic.com to find the exact Bosch replacement part that fits your dishwasher.
01 - Bosch Dishwasher Water Inlet Valve
The water inlet valve is an electrically-controlled valve that opens to allow water to enter the dishwasher. Depending on the model, the valve stays open either for a set length of time or until the dishwasher has enough water. However, if the water inlet valve doesn’t shut off after the dishwasher has enough water, the dishwasher will overflow. If water drips into the dishwasher when the door is open, or if water collects at the bottom of the dishwasher while it is not use, you may need to replace the water inlet valve.
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A dishwasher's main control board provides power to nearly every electrical component in the dishwasher. If the control board continues to send power to the water inlet valve during the drain cycle, the dishwasher could overflow. While this is not that common of a problem, you can inspect the board for signs of burning or a shorted-out component. You can also use a multimeter to test the water inlet valve for incoming power during the dishwasher's cycle.
If the lower wash arm has a crack or split on the side it can cause water to splash out the bottom of the door, giving the impression that the dishwasher is overflowing. Inspect the wash arm assembly for any damage and replace if necessary.
Make sure to use the proper dishwasher detergent. Use the proper amount of detergent for your water hardness; too much soap in soft water can cause oversudsing and leaking.
Common
05 - Bosch Dishwasher Control Board
A dishwasher's control board provides power to nearly every electrical component in the dishwasher. If the control board continues to send power to the water inlet valve the dishwasher could overflow. While this is not that common of a problem, you can inspect the board for signs of burning or a shorted-out component. You can also use a multimeter to test the water inlet valve for incoming power during the dishwasher's cycle.
The float switch actuates in order to prevent the dishwasher from overflowing. If the float switch is defective or stuck, it might not stop the dishwasher from overflowing. If the float switch is defective, replace it.