Display shows E4 and the unit shuts down shortly after starting a cycle.

Safety First: Unplug the ice maker before removing any internal covers.

Steps to resolve E4:

• Access evaporator area: Remove the front or top inner cover to expose the evaporator plate and attached sensor (thermistor).
• Check sensor placement: Ensure the thermistor is firmly clipped or taped to the evaporator surface where the factory placed it. Reattach if it has fallen off.
• Inspect wiring: Follow the thermistor wires back to the control board, checking for cuts, abrasions, or loose connectors. Reseat the plug on the board.
• Measure resistance: Disconnect the thermistor and measure its resistance at room temperature. Compare to the service chart; if it reads open or shorted, it is defective.
• Replace thermistor: Remove the old evaporator thermistor, install the new Koldfront-compatible sensor in the same location, and secure it firmly to the evaporator surface.
• Reassemble and test: Reinstall covers, restore power, and run a cycle to verify that E4 does not return.

Tip: If the thermistor tests good but E4 persists, the main control board may need replacement.