E4
Midea Defrost Protection / Outdoor Coil Overheat or Frost Protection

Unit stops in heating mode and displays E4; may blow cold air before shutting down

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Outdoor coil heavily frosted, Faulty outdoor coil temperature sensor (T3), Poor drainage causing ice buildup at base, Defective 4-way reversing valve or control logic

How to Fix / Troubleshooting

Safety first: Turn off power before touching the outdoor unit. Surfaces may be very hot or covered in ice.

Steps to check:

  • 1. Allow automatic defrost: In heating mode, the unit will periodically enter defrost. Let it run for 10–15 minutes to see if frost clears and E4 disappears.
  • 2. Inspect outdoor coil: If the coil is completely encased in ice, turn the unit OFF and allow ice to melt naturally. Do not chip ice with sharp tools. Check that the base pan drain holes are not blocked by dirt or ice.
  • 3. Check outdoor sensor placement: Locate the T3 sensor clipped to the outdoor coil (with power OFF). Ensure it is firmly attached and not dangling or corroded.
  • 4. Clear snow and obstructions: In cold climates, remove snow buildup around the outdoor unit and ensure good airflow.

When to call a technician: Persistent E4 may indicate a faulty T3 sensor, reversing valve issue, or refrigerant problem. A technician should test the sensor resistance, defrost cycle operation, and refrigerant charge.

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Repair Difficulty

Medium 3/5

Required Part

Outdoor Coil Temperature Sensor (T3)
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