Miele Refrigerator Error Code F115

The F115 error code on a Miele refrigerator indicates that the refrigerator evaporator NTC (negative temperature coefficient thermistor) is reporting a resistance value outside of the acceptable operating range. Specifically, the sensor is reading a temperature equivalent below -66°F (-55°C) or above 140°F (60°C), both of which fall outside the normal refrigeration operating window. The NTC thermistor works by changing its electrical resistance in response to temperature, and the control board uses those resistance readings to monitor and regulate the evaporator's thermal state. When the board receives a signal that corresponds to these extreme out-of-range values, it flags the sensor as faulty and triggers the F115 code.

The evaporator NTC is mounted near the evaporator coil in the refrigerator compartment and plays a critical role in defrost cycle timing and temperature management. A reading below the minimum threshold typically indicates a short circuit in the sensor or its wiring, which drives resistance artificially low. A reading above the maximum threshold typically points to an open circuit condition, where a broken wire, corroded connector, or failed sensor causes resistance to spike to an unmeasurable level. Both failure modes produce an implausible signal that the control board cannot use for accurate temperature regulation.

Common contributing factors include physical damage to the sensor harness from ice buildup around the evaporator, corrosion at the connector terminals due to moisture exposure in the refrigerator cavity, or simple age-related degradation of the thermistor element itself. Because the diagnostic data directly identifies the evaporator NTC as the faulty component, sensor replacement is the recommended first step, though wiring and connector integrity should be inspected before condemning the sensor outright.