Miele Washer Error Code F4045

F4045 means the resistance measured from NTC 1, the primary water temperature sensor, is higher than the maximum permissible value, which the control board interprets as an open circuit. This tells the machine that the sensor circuit is broken and temperature cannot be reliably monitored. The washer will stop operation until the fault is corrected to prevent unsafe heating conditions.

No, you should not attempt to operate the washer while F4045 is active. The error indicates the temperature sensor circuit is open, meaning the machine cannot monitor water temperature. Running a heated wash cycle without functional temperature sensing creates a risk of water overheating, and the machine is designed to halt operation for this reason.

Repair costs vary depending on the root cause. If only a connector needs cleaning or reseating, cost is minimal. Replacing the NTC 1 temperature sensor typically involves parts costs in the range of $20 to $80 depending on the specific model. If the control board is at fault, parts and labor combined can range from $200 to $500 or more. A technician diagnosis fee is typically charged separately to identify the exact cause.

Some causes of F4045 are accessible to a confident DIYer, particularly inspecting and reseating wiring connectors or cleaning corroded pins. Testing the NTC 1 sensor with a multimeter is straightforward if you can access the sensor. However, replacing the sensor or diagnosing a control board fault typically requires disassembly of the machine and is better suited to a qualified appliance technician.

A power reset may temporarily clear the error display, but the fault will return immediately once the control board checks the NTC 1 sensor circuit again, which happens at startup or during the wash cycle. The underlying sensor or wiring problem must be diagnosed and repaired before the error will clear permanently.