Kenmore Refrigerator Error Code F1

The F1 error code on a Kenmore refrigerator indicates that the main PCB has detected an abnormal signal from the freezer temperature sensor (thermistor). Specifically, the control board is reading the sensor circuit as either open (no continuity, meaning the circuit is broken) or shorted (resistance has dropped to near zero, meaning the circuit has an unintended direct connection). Under normal operating conditions, an NTC thermistor changes resistance predictably with temperature, and the control board uses that resistance value to monitor freezer compartment temperature and regulate compressor and defrost cycles accordingly.

When the freezer sensor signal falls outside the expected resistance range, the board cannot trust the temperature data and triggers the F1 fault. This protects the refrigerator from operating blindly, since an inaccurate temperature reading could lead to freezer temperatures that are too warm or too cold without any corrective response from the control system. The fault is most commonly caused by a failed thermistor, damaged wiring in the sensor harness, or a corroded or loose connector at the sensor end or at the main PCB.

Diagnosis should begin by inspecting all wiring connections in the sensor circuit and at the main PCB, as connector issues are a frequent and easily corrected root cause. If connections are secure and undamaged, the thermistor itself should be tested with a multimeter for proper resistance values relative to freezer temperature. If the sensor tests out of specification or reads open or shorted, replacement is necessary. If the sensor and wiring both check out, the main PCB may have a failed input circuit and could require replacement.