Bosch Dishwasher Error Code 8

Error code 8 means the control board has detected a fault with the NTC temperature sensor, which monitors water temperature during the wash cycle. The board expects to read approximately 55 kΩ of resistance from the sensor at room temperature. When the reading is absent or out of range, the machine stops and displays code 8.

Running the dishwasher with error code 8 active is not advisable. Without a functioning temperature sensor, the control board cannot regulate the heating element accurately, which means water may not reach proper sanitizing temperatures or, in a worst case, the heater could run longer than intended. Most Bosch units will not complete a cycle while this code is active anyway.

Disconnect power to the dishwasher, then locate and unplug the NTC sensor connector. Set a multimeter to the resistance (ohms) setting and touch the probes to the two sensor terminals. At a room temperature of approximately 72°F, a good NTC should read close to 55 kΩ. A reading that is significantly higher, lower, or shows OL (open loop) confirms the sensor has failed and needs replacement.

Start by unplugging the dishwasher and locating the NTC sensor, which is typically mounted in the wash tub near the heating element. Disconnect the sensor and measure its resistance with a multimeter; at 72°F it should read approximately 55 kΩ. If the reading is far off or shows an open circuit, replace the NTC. If the sensor reads correctly, inspect the wiring harness and connector between the sensor and the control board for damage or corrosion.

An NTC temperature sensor for a Bosch dishwasher typically costs between $15 and $40 for the part, and replacing it is a relatively accessible repair requiring only basic tools and a multimeter. If a technician performs the repair, expect to add $80 to $150 in labor. If the fault turns out to be the control board rather than the sensor, board costs range from $100 to $300 or more, which may affect whether repair is worthwhile on an older unit.