LG Refrigerator ER FS Error: Freezer Sensor Error
LG refrigerator error — here’s what you need to know. The Er FS error code on your LG refrigerator indicates a fault with the freezer temperature sensor (thermistor). This is a Medium severity issue. What Does Er FS Mean on an LG Refrigerator? The freezer thermistor is a small resistive sensor that continuously reports the […]
~70%
DIY Fixable
From $120
Typical Repair Cost
1–2 hours
Pro Repair Time
Quick Assessment
Answer to continue safely
Is it safe to keep using?
Maybe. The freezer may still cool, but temperature control is unreliable. Monitor freezer temperature with a standalone thermometer. If temperature stays between -5°F and 5°F, food is safe for a short period while arranging repair.
Can I reset the code?
Yes. A power reset may temporarily clear the error if caused by a loose connector. Reseat the thermistor connector firmly before resetting. The error will return if the sensor itself has failed.
When to stop immediately?
Stop if you notice: Freezer temperature rises above 10°F and food begins to thaw, Compressor runs non-stop for more than 4 hours without reaching temperature.
Symptoms You May Notice
Freezer Temperature Fluctuates or Runs Too Cold
Without accurate temperature data, the control board may run the compressor too long, making the freezer excessively cold, or not long enough, allowing it to warm up. Food may show freezer burn from temperature extremes.
Compressor Runs Continuously
If the sensor reports an open circuit, the board interprets the freezer as always too warm and keeps the compressor running non-stop. The unit runs loudly and the compressor stays on even when temperatures are already at target.
Display Shows Dashes or Wrong Temperature
The freezer temperature display may show dashes, a blank reading, or a fixed number that does not change regardless of actual compartment temperature. This confirms the board is not receiving valid sensor data.
Inconsistent temperature performance
The refrigerator runs too hot, too cold, or cycles erratically because the control board receives inaccurate temperature readings from the faulty sensor.
Possible Causes
Failed Freezer Thermistor
The thermistor's resistance drifts permanently out of range due to component aging or moisture exposure. Testing with a multimeter should show a resistance near 10,000 ohms at room temperature for most LG thermistors — a very high or zero reading confirms failure.
DIY PossibleDamaged Sensor Wiring or Connector
Ice buildup pressing against the sensor wire, a sharp freezer rack edge cutting the insulation, or a corroded connector pin can interrupt the sensor signal. The thermistor itself may be fine but unable to communicate.
DIY PossibleControl Board Sensor Input Failure
The analog input circuit on the main control board that reads the thermistor voltage can fail, making a working sensor appear faulty. This is confirmed when a known-good replacement thermistor still produces the error.
Requires ProfessionalSafe Checks You Can Do
-
1
Locate and Inspect the Freezer Thermistor
Unplug the refrigerator. Remove the freezer rear panel (several screws and clips). The thermistor is a small sensor clipped to the evaporator coil fins, with two wires leading to a connector. Check for visible damage: cracks, ice embedding, melted insulation, or corrosion on the connector.
-
2
Test Thermistor Resistance with a Multimeter
Disconnect the thermistor connector and set your multimeter to the 20k ohm range. Touch the probes to the two thermistor wires. At room temperature (around 70°F), a working LG thermistor reads approximately 8,000–12,000 ohms. A reading of zero or infinite (OL) confirms the thermistor has failed.
-
3
Check Wiring Harness Continuity
If the thermistor tests good, test the wiring harness by checking continuity from the thermistor connector to the main board connector. Any break in continuity along the wire run indicates a damaged harness that needs repair or replacement.
When to Call a Professional
Contact a qualified technician if:
- Thermistor reads correctly on multimeter but error persists after reinstallation
- Wiring harness has full continuity but board still reports sensor error
- Replacement thermistor installed but error code returns immediately
Need Professional Help?
Find qualified technicians in your area for proper diagnostics and repair.
Refrigerator Repair Service Schedule Appointment