Bosch Dishwasher Error Code E2

E2 on a Bosch dishwasher means the control board has detected a problem with the NTC temperature sensor circuit. The NTC thermistor monitors water temperature throughout the wash cycle, and the board throws E2 when the sensor's resistance reading falls outside the expected range on the NTC resistance chart. A working sensor measures roughly 55k ohms at 72 degrees Fahrenheit.

Running the dishwasher with an active E2 code is not recommended. Without a functioning NTC sensor, the control board cannot accurately regulate water temperature, which means water could fail to reach sanitizing temperatures or, depending on the failure mode, the heater could run unchecked. Most Bosch models will halt the cycle automatically when E2 appears, preventing normal operation until the fault is cleared.

Disconnect power to the dishwasher, then locate the NTC thermistor on the sump assembly. Unplug the two-wire connector from the sensor and set a multimeter to the ohms setting. Touch the probes to the sensor terminals and note the resistance reading. At room temperature around 72 degrees Fahrenheit, a good Bosch NTC sensor reads approximately 55k ohms. Cross-reference the reading against the Bosch NTC resistance chart for accuracy at different temperatures. A reading of zero, infinite resistance, or a value well outside the chart range confirms a failed sensor.

Start by unplugging the dishwasher and locating the NTC thermistor, which is typically mounted on the sump or heating element housing. Disconnect the sensor and measure its resistance with a multimeter, comparing the reading to the Bosch NTC resistance chart for the current temperature. If resistance is far from the expected 55k ohms at 72 degrees Fahrenheit, replace the NTC sensor. If the sensor tests good, inspect the wiring harness and connector for corrosion or damage before suspecting the control board.

If the NTC thermistor is the cause, the part typically costs between $15 and $40 and is a manageable DIY repair requiring a multimeter and basic hand tools. A professional appliance technician will usually charge $100 to $200 in labor on top of the part cost. If the control board is the root cause, board replacement can run $150 to $300 for the part alone, making professional diagnosis worthwhile before purchasing components.