Prodigy Ice Maker Error Code 5

Error code 5 on a Prodigy ice maker indicates a sump water temperature sensor failure. The sump sensor is a thermistor submerged in the water sump at the base of the ice maker, responsible for continuously monitoring the temperature of the water used in the freeze cycle. The control board reads resistance values from this sensor to determine water temperature and regulate the ice-making process accordingly. When the board detects a signal outside the expected resistance range, either an open circuit, a short to ground, or a reading that falls outside calibrated parameters, it triggers error code 5 and halts operation.

The most common causes of this fault include a failed thermistor, damaged wiring in the sensor harness, or a corroded or loose connector at the sensor or control board. Because the sensor sits in or near standing water inside the sump, the connector and wiring insulation are particularly vulnerable to moisture intrusion and corrosion over time. A thermistor that has drifted out of its correct resistance range due to age or water damage will produce inaccurate temperature data and trigger the fault even if the wiring is intact.

Diagnosing this error requires inspecting the sensor wiring and connectors for visible corrosion, breaks, or moisture damage, then testing the thermistor resistance with a multimeter and comparing it against the specified resistance curve for the operating temperature. If the resistance is open, shorted, or significantly out of range, the sensor requires replacement. The control board should only be suspected after the sensor and its wiring are confirmed good.