Display shows E4 and the unit may have heavy frost buildup or poor cooling performance.

Safety: Disconnect power before removing interior panels. Melted ice and water can make surfaces slippery; place towels in the cabinet.

Steps to resolve E4:

• Inspect for frost: Remove interior shelves and the rear evaporator cover. If the evaporator coil is encased in solid ice, a defrost problem is likely.
• Manual defrost: With the unit unplugged, allow the ice to melt naturally or use a hair dryer on low, keeping it at a safe distance to avoid melting plastic. Do not use sharp tools to chip ice.
• Locate defrost components: Identify the defrost heater (usually a tube or wire heater at the base or wrapped around the evaporator) and the defrost thermistor or thermostat attached to the coil.
• Test the defrost heater: Disconnect the heater leads and check for continuity with a multimeter. An open circuit indicates a failed heater.
• Test the defrost thermistor: Measure resistance and compare to expected NTC values. If open, shorted, or out of range, replace it.
• Inspect wiring and connectors: Look for brittle or broken wires near the evaporator where ice expansion can cause damage. Repair or replace damaged sections.
• Check the control board: If heater and sensor test good, the defrost relay or control logic on the main board may be faulty. Replace the main control board if no other faults are found.

After repair: Reassemble panels, restore power, and monitor for several days to ensure frost does not re-accumulate and that the E4 code does not return.