Er FS Serious Moderate DIY

LG Refrigerator Er FS — Freezer sensor open/short

LG Refrigerator · Error code Er FS

What Er FS Means

The freezer compartment thermistor is reading open or shorted. The board can't accurately read freezer temperature and falls back to a default cycle, so freezer temps drift.

Symptoms

  • Er FS on display
  • Freezer too warm or too cold
  • Ice cream soft, or freezer burn on items
  • Compressor cycles abnormally

Common Causes

1
Open NTC thermistor

Sensor element failed.

2
Sensor harness break

Pinched/cut wire behind the freezer back panel.

3
Bad connector contact

Corrosion or loose pin in the wiring connector.

4
Main board ADC channel fault

Uncommon, but possible after a surge.

How to Fix It

  1. Unplug the refrigerator and pull the freezer rear panel.
  2. Locate the freezer thermistor; reseat the plug at the harness.
  3. Measure resistance with a meter and compare to the LG sensor chart.
  4. Replace the thermistor if open, shorted, or out of spec.
  5. If the new sensor still throws Er FS, suspect main control board.
  6. Restore power and verify the code clears.

Parts You May Need

If diagnosis points to a failed part, these are the common replacements. As an Amazon Associate we earn from qualifying purchases.

Common replacement Freezer thermistor View on Amazon→

More LG Refrigerator Codes

22 22 — Compressor relay / inverter control fault 33 33 — Compressor / defrost test fault 67 67 — Door open / not fully closed 88 88 — Power-on display test (not a fault) Er CF Er CF — Condenser Fan Fault Er CO Er CO — Compressor / Communication Fault

All LG codes → All refrigerator codes →

Verified against manufacturer documentation: lg.com

Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician.