Bosch Dishwasher Error Code #K

Code #K on a Bosch dishwasher with an Apexx display signals an NTC thermistor fault. The NTC is a temperature sensor, and this code means the control board detected either a short circuit or an open circuit in that sensor's circuit. The dishwasher cannot accurately read water temperature and will typically halt operation until the fault is resolved.

Running the dishwasher with an active #K code is not recommended. The NTC thermistor is how the machine monitors water temperature, and without valid temperature feedback the control board cannot regulate heating safely. Continued use risks inadequate sanitation if the water does not reach proper temperature, or overheating if the heating element runs without reliable sensor input. Stop using the appliance until the fault is diagnosed and repaired.

Cycling power or performing a reset may temporarily clear the #K code from the display, but the code will return as soon as the control board runs its diagnostic and detects the same NTC fault again. A power reset does not fix a failed sensor, broken wire, or corroded connector. Use the reset only to confirm whether the fault is intermittent or persistent, not as a substitute for diagnosing the underlying problem.

Start by disconnecting power to the dishwasher and locating the NTC thermistor, which is typically mounted in the sump or heating element area. Inspect the wiring harness and connectors for visible damage, corrosion, or loose pins and reseat any suspect connections. Use a multimeter to test the NTC sensor's resistance at room temperature, which should read several thousand ohms for a healthy sensor. If the sensor reads zero or infinite resistance, replace it. If the wiring and sensor both test correctly, the control board may need inspection by a technician.

If the NTC thermistor itself has failed, the part typically costs between $15 and $50 depending on the model, and replacing it is a moderately accessible DIY repair for someone comfortable working with appliance wiring. If the issue is a damaged wiring harness, parts cost is similar but routing and securing new wiring takes more time. A professional repair visit adds $100 to $200 or more in labor. If the fault traces back to the control board, board replacement costs can reach $150 to $350 for parts alone, making professional diagnosis worthwhile before committing to that expense.