E3 error appears; ice maker may start but stops mid-cycle or fails to harvest ice.

Safety first: Disconnect power before opening the cabinet or touching internal components.

Steps to address E3:

• Access the evaporator area: Remove the top cover and front inner panel to expose the evaporator (the cold metal grid/plate where ice forms). The sensor is usually clipped or glued to the side or back of this plate.
• Inspect sensor placement: Ensure the small thermistor bulb is firmly attached to the evaporator surface. If it has fallen off, reattach it using aluminum tape or the original clip so it makes good thermal contact.
• Check wiring and connector: Trace the sensor wires back to the control board. Look for cuts, abrasions, or loose connectors. Reseat the connector firmly.
• Test the thermistor: With the sensor disconnected, measure resistance at room temperature. Compare to the ambient sensor if they are the same type; values should be similar. An open or shorted reading indicates a bad sensor.
• Replace the sensor if faulty: Install a new Costway evaporator temperature sensor / NTC thermistor. Route the wires away from moving parts and secure them with ties.
• Check for ice buildup: Heavy ice buildup around the sensor can cause false readings. Defrost the unit completely by leaving it unplugged with the lid open until all ice melts, then dry the area before restarting.
• If E3 remains: Persistent E3 with a known-good sensor suggests a defective main control board, which may require replacement or professional diagnosis.