Freezer displays E4 and may not defrost properly; frost builds up on evaporator

Safety first: Disconnect power before opening the evaporator compartment. Beware of sharp metal edges and ice.

Steps to address E4:

• Access evaporator: Remove baskets and shelves. Unscrew and remove the rear inner panel to expose the evaporator coil and defrost components.
• Identify defrost sensor: The defrost sensor (thermistor) is usually clipped to the upper portion of the evaporator or attached near the defrost heater.
• Check mounting: Ensure the sensor is firmly clipped to the coil or bracket. A loose sensor can misread temperature and trigger E4.
• Test resistance: Disconnect the sensor and measure resistance with a multimeter. Compare to expected NTC values at the current temperature (colder coil = higher resistance). A reading of OL or 0 Ω indicates failure.
• Replace sensor: If faulty, install a new Midea defrost sensor/thermistor. Clip it securely in the original location to ensure accurate defrost control.
• Inspect wiring: Follow the harness back toward the cabinet pass-through and control board. Repair any pinched or broken wires using proper connectors and heat-shrink tubing.

Note: If the sensor and wiring are good but E4 persists, the main control board's defrost circuit may be defective and should be evaluated by a technician.