Bosch Dishwasher Error Code E:21

E:21 on a Bosch dishwasher indicates a fault in the heat pump circuit, signaled by a flashing Sanitized LED. The error points to either a failed heat pump motor winding or a problem with the wire harness connecting the heat pump to the power module. The power module itself can also be the source of the fault if the wiring and motor check out correctly.

It is not recommended to continue running the dishwasher while E:21 is active. The error indicates a failure in the heat pump circuit, and operating the machine in this condition could prevent proper water heating and sanitization. Continued use may also place additional stress on other components before the root cause is addressed.

Repair costs vary depending on which component has failed. Heat pump replacement parts typically range from $100 to $250, while power module replacements can range from $80 to $200 or more, depending on the model. Adding professional labor, the total repair cost generally falls between $150 and $450. Diagnosing the fault with a multimeter before ordering parts helps avoid paying for unnecessary components.

Start by measuring the resistance across any two terminals on the heat pump motor with a multimeter. A healthy motor winding should read approximately 15.2 ohms at room temperature. If the reading is incorrect, replace the heat pump. If the resistance is correct, check continuity through the wire harness between the heat pump and power module. If the harness is good and the motor measures correctly, replace the power module.

A reset may temporarily clear the E:21 code, but the error will return if the underlying fault in the heat pump circuit has not been repaired. The code is triggered by a measurable electrical fault, so resetting the appliance without fixing the wiring, motor winding, or power module will not resolve the problem.