Display shows E4 and the unit stops; ice harvest may not complete and ice may stick to the evaporator.

Safety: Unplug the ice maker before removing panels. Hot surfaces and sharp metal edges may be present.

Diagnostic steps:

• Observe harvest cycle: If possible, run a cycle and watch the harvest stage. If ice does not release from the evaporator, suspect a harvest/heating issue.
• Inspect harvest sensor: Locate the harvest or defrost sensor near the evaporator or on the hot gas line. Check for secure mounting and clean any scale or debris.
• Check hot gas valve: Find the hot gas solenoid valve on the refrigeration line. With power disconnected, inspect the coil and wiring for damage or loose connectors.
• Electrical tests: Using a multimeter, check the resistance of the hot gas valve coil and the harvest sensor (refer to service specs). Replace any component that is open or shorted.
• Control board evaluation: If both sensor and valve test good, the main control PCB may not be energizing the valve correctly. Inspect for burnt traces or components and replace the board if necessary.

Note: Refrigerant circuit components (like the hot gas valve) should be serviced by a licensed technician if brazing or refrigerant handling is required.