Bosch dishwasher — Error Code E15

What it means

The Bosch E15 error code is a critical fault indicating that water has accumulated in the bottom base pan (the plastic or metal tray beneath the main washing tub). Bosch dishwashers are equipped with an AquaStop leak protection system, which utilizes a polystyrene float switch located in this base pan. When water pools in the basin, the float rises and activates a microswitch. Once triggered, the main control board immediately halts the wash cycle, shuts off the water inlet valve to prevent flooding, and forces the drain pump to run continuously to evacuate any remaining water in the tub. You will often hear the drain pump humming even if the dishwasher is turned off via the power button. The E15 code will not clear as long as the float switch is elevated. Resolving this error requires physically removing the water from the base pan and diagnosing the source of the internal leak.

Likely Causes

1. 1
   Sump Basin Seal Failure

   The silicone seal between the stainless steel tub and the plastic sump basin degrades over time, allowing wash water to seep into the base pan. Bosch manufactures a specific wire-guided seal kit to fix this common issue.
2. 2
   Leaking Circulation Pump

   The main wash motor (circulation pump) or its integrated heating element can develop hairline cracks or worn O-rings, leaking water under pressure directly into the chassis.
3. 3
   Water Inlet Valve Leak

   A faulty or cracked water inlet valve can drip water into the base pan during the fill cycle. This often presents as a slow leak that triggers the E15 code overnight.
4. 4
   Clogged Filter or Oversudsing

   Excessive suds from incorrect detergent or a severely clogged filter assembly can cause water to overflow the tub lip and run down the sides into the base pan.
5. 5
   Faulty Float Switch

   Rarely, the polystyrene float gets stuck in the 'up' position due to debris, or the microswitch itself shorts out, falsely reporting a leak to the control board.

How to clear / reset

Because the E15 code is a hard lockout triggered by a physical safety switch, a simple button reset will not work. To temporarily clear the code and stop the drain pump from running continuously, you must remove the water from the base pan. Disconnect power at the breaker. Pull the dishwasher out from under the counter and carefully tilt it backward at a 45-degree angle to let the trapped water drain out onto a towel. Once the base is dry, the float switch will drop, and the code will clear when power is restored. However, if you do not fix the underlying leak, the E15 code will return as soon as the base fills with water again.

Common replacement parts

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