LG Fridge Error Er FS: Defrost Sensor Fault
Er FS on an LG No-Frost fridge means the probe monitoring evaporator temperature during automatic defrost isn't sending a valid reading.
Common symptoms:
- Er FS shows on the outer digital panel
- The freezer cools unevenly
- Visible frost forms on the fridge's rear wall
Probable causes:
The small sensor next to the defrost heater becomes covered by a thick layer of ice following a previous system fault.
Without the heater working, ice progressively builds up and eventually affects the nearby sensor as well.
The wiring behind the rear panel has loosened slightly over time from compressor vibration.
Safe Inspection Checklist (Check off when completed):
Remove the food, turn off the unit, and leave the doors open for 24 hours with absorbent towels underneath to fully clear built-up ice, including any covering the sensor.
With the ice melted, carefully remove the freezer's interior rear panel and check whether the white cylindrical sensor is properly seated in its clip next to the metal heater element.
Reassemble the panel, plug the fridge back in, and monitor for 24-48 hours whether ice reforms or Er FS reappears.
If Er FS reappears shortly after a full defrost, the defrost heater or sensor needs replacement by a technician, since an ongoing fault can eventually affect the compressor.