Fisher & Paykel Refrigerator Error Code 12

Error code 12 on a Fisher & Paykel refrigerator indicates a "compartment sensor hot" condition, meaning the compartment temperature sensor has reported a resistance value below 660 Ohms. Temperature sensors in refrigerators are typically Negative Temperature Coefficient (NTC) thermistors, which means their resistance decreases as temperature increases. A reading below the minimum threshold of 660 Ohms tells the control board that the sensor is reporting an extremely high temperature, one outside the realistic operating range of the compartment. This points to a fault within the sensor itself rather than an actual temperature problem.

The most direct cause is a failed thermistor that has drifted out of specification, either due to age, moisture ingress, or physical damage to the sensor or its wiring. A short circuit in the sensor wiring harness can also pull the resistance reading below 660 Ohms, mimicking a failed sensor. Because the control board relies on accurate sensor data to regulate compressor cycling and fan operation, a faulty reading can disrupt temperature management throughout the refrigerator compartment.

Diagnosis begins by measuring the resistance of the compartment temperature sensor directly with a multimeter. If the reading is below 660 Ohms under normal ambient conditions, the sensor is confirmed faulty and requires replacement. Inspect the wiring harness and connector for corrosion, pinching, or chafing before replacing the sensor, as wiring faults can produce the same low-resistance reading and would need to be corrected separately.