Display shows E4 and the unit will not start an ice-making cycle.

Safety: Disconnect the ice maker from mains power before opening any panels.

Steps:

• Allow unit to reach room temperature: If the unit was stored in a very hot or very cold environment, let it sit unplugged for at least 1 hour at normal room temperature, then retry.
• Locate ambient sensor: Remove the rear or side cover to find the small NTC sensor mounted near the air intake or on the inner cabinet wall, separate from the evaporator sensor.
• Check mounting: Ensure the sensor is properly clipped or taped to its designated location and not hanging loose inside the cabinet.
• Inspect wiring: Follow the sensor wires to the main control PCB. Reseat the connector and check for any cuts, abrasions, or pinched sections.
• Test sensor: If you have a multimeter, measure resistance at room temperature and compare with the service chart. If readings are open, shorted, or far off spec, replace the ambient temperature sensor.
• If E4 persists: After sensor replacement, a persistent E4 may indicate a defective main control PCB. Contact an authorized OBH Nordica service provider for further diagnosis.