At the end of a normal dishwasher cycle (the dishes came clean), the dishwasher never ended the pump out cycle. Even with the door open, it keeps pumping. Adding water from a bucket to the front, it keeps pumping. After cancelling and cycling the breaker, it keeps pumping.

I know from prior experience this is a "timed fill" machine that does not know how much water went in, just opens the valve for a given amount of time.

What part may be defective for the drain? The https://www.bosch-home.com/ website lists parts but no diagnostic methods. There is a "Water Level Control Assembly Timed-Fill" 00440670

Bosch Dishwasher water level sensor

What sensor could I short out or open, to test the theory it's a bad water level sensor?

1 Answer 1


OP here. Turns out this model of dishwasher uses a single water level sensor for several functions, including the tub water level, and the drain pan below the machine. In the drain pan is a dodgy looking foam float, that pushes a red rod into the tub water sensor.

Thus, when the drain pan gets wet, the dishwasher starts pumping out. Since the pump does not remove water from the drain pan, it just keeps pumping forever.

I was able to clear the water from the pan using 20-30 round trips with a sponge.

Bosch pump runs forever, drain pan repair appliance fix

February 2020 Update: found the leak:

enter image description here

Which is a terrible design on the part of Bosch, as a very weak connection point is outside the drain pan capture area.

This is miserable design. As well the sound insulation dips into the drain pan like a sponge, leading to mold.

Very poor design for serviceability.

Now on to why there's apparent evidence of water sitting higher up:

enter image description here

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