Miele Refrigerator Error Code F4

F4 indicates that the freezer evaporator NTC temperature sensor has been detected as defective, either short-circuited or open-circuited. The control board can no longer receive valid temperature readings from the freezer evaporator, so it runs the compressor continuously as a default response. The sensor must be tested against the resistance table and replaced if it falls outside the specified range.

Resetting the unit by cycling the power may temporarily clear the error display, but the code will return if the underlying NTC sensor fault is still present. The compressor will also continue running continuously until the root cause is repaired. A reset is not a fix and should only be used as part of the diagnostic process.

If the NTC sensor itself is the cause, parts and labor costs are typically in the range of $100 to $300 depending on your location and service provider. If the wiring or connector is the issue, the cost may be lower since parts are minimal. A control board replacement, if required, can range from $300 to $600 or more, making accurate diagnosis before ordering parts important.

A knowledgeable DIYer with a multimeter can test the NTC sensor's resistance and inspect the wiring harness and connectors for damage. If the sensor tests as open or shorted, replacing it is a straightforward repair. However, if the wiring and sensor both test correctly, the fault may lie with the control board, which is a more complex and costly repair best handled by a qualified technician.

Continued use with F4 active is not recommended for extended periods. The compressor running without interruption accelerates wear and increases energy consumption. Food safety may also be at risk if temperature regulation becomes unpredictable. It is best to address the fault promptly or transfer perishables to another unit in the meantime.