Miele Freezer Error Code F164

F164 indicates that the middle zone evaporator NTC sensor has been detected as defective by the control board. The NTC is a thermistor that monitors temperature at the evaporator coil in the middle cooling zone. When its resistance reading falls outside the expected range, or no reading is detected at all, the control board logs this fault. The freezer may not defrost or cool correctly until the sensor is replaced.

Continuing to run the freezer with an active F164 fault is not recommended for extended periods. Without a functioning middle zone evaporator NTC, the control board cannot accurately manage defrost cycles or temperature in that zone, which can lead to frost buildup, compressor strain, and potential food spoilage. It is best to address the fault as soon as possible.

A power reset may temporarily clear the fault display, but the code will return if the underlying sensor issue has not been resolved. The control board will re-detect the defective or out-of-range NTC reading during normal operation and log F164 again. A permanent fix requires replacing the faulty sensor or repairing the associated wiring.

Replacing an NTC sensor is a task some experienced DIYers can handle, as it typically involves accessing the evaporator area, disconnecting the old sensor, and installing a new one. However, the evaporator section of a freezer requires careful disassembly and reassembly to avoid damaging refrigerant lines or other components. If you are not comfortable working inside the freezer cabinet, a qualified appliance technician is the safer choice.

Repair costs typically include the price of the replacement NTC sensor plus labor if a technician is hired. Sensor parts for Miele appliances generally range from around 20 to 80 dollars depending on availability and supplier, while professional labor can add 80 to 200 dollars or more depending on your location and the complexity of accessing the evaporator. Getting a quote from a Miele-authorized service provider before committing to repairs is a good approach.