What does LG Range F1 Error Code - Causes & Fix mean?

F1 on an LG range means an upper oven thermistor error. The most common fix is replacing the failed upper oven temperature sensor.

How do I fix LG Range F1 Error Code - Causes & Fix?

Follow the step-by-step diagnosis below. The most likely fix is identified by checking power, sensor resistance, and control-board signals in order — using a multimeter and the part numbers documented in the parts reference table.

Can I keep running the equipment with F1 active?

Generally no. Faults on Appliance units are emitted when a sensor, safety, or control circuit is outside its operating envelope. Running through an active fault risks compressor, heater, or control-board damage. Diagnose and clear the fault first.

What part is most commonly replaced for LG Range F1 Error Code - Causes & Fix?

The most frequently replaced parts for LG Range F1 Error Code - Causes & Fix are listed in the Parts Reference section of this guide with OEM part numbers and typical price ranges. Check the table for direct replacements.

Is LG Range F1 Error Code - Causes & Fix a DIY repair or do I need a technician?

Sensor swaps, fan motor replacements, and condenser cleaning are typical DIY-level repairs. Anything involving refrigerant, gas, or high-voltage (>240V) work requires a licensed technician for both safety and code-compliance reasons.

LG Range F1 Error Code - Causes & Fix

LG Range F1 Error Code — What It Means

The F1 error code on LG ranges indicates an upper oven thermistor error. The control board has detected a fault in the upper oven temperature sensor circuit. This typically happens when the sensor itself has failed, when the wiring or connector is damaged, or when the sensor circuit is shorted for over one minute during cooking. The code means the oven cannot accurately read the upper oven temperature and will not operate normally until the fault is cleared.

Jump to Fix

Common Causes

Failed upper oven temperature sensor The thermistor itself has opened, shorted, or drifted out of specification and no longer provides accurate resistance readings to the control board.
Shorted sensor circuit The sensor wiring or connector has shorted internally or against the oven frame, causing the control to read a continuous fault for over one minute.
Loose or damaged wiring harness The connector at the sensor or control board is not fully seated, or the harness has broken, burned, or pinched wires that interrupt the sensor signal.
Corroded or burned connector terminals Heat or moisture has damaged the plug or socket at either end of the sensor circuit, creating intermittent or high-resistance connections.
Faulty main control board The electronic range control cannot correctly read a sensor that tests normal, indicating an internal board fault in the thermistor input circuit.

Step-by-Step Fix

Reset the range by pressing CLEAR/OFF or turning off the unit, then try the oven function again to see if the code clears on its own.
Cycle the circuit breaker off for 30 seconds and restore power if the F1 code returns immediately after the first reset.
Unplug the range and pull it away from the wall to access the rear panel or upper-oven cavity where the thermistor and wiring are located.
Inspect the upper oven thermistor connector and harness for loose plugs, broken wires, burn marks, or pinched insulation, and reseat any loose connections.
Test the thermistor resistance with a multimeter at room temperature by disconnecting the sensor and measuring across its two terminals (a healthy LG oven sensor typically reads around 1.06 to 1.12 kΩ at room temperature).
Replace the upper oven thermistor if the resistance is open, shorted (near zero), or far outside the expected range, using the OEM part number for your model.
Replace the main control board if the sensor tests normal, all wiring and connectors are intact, and the F1 code persists after reconnecting everything and restoring power.

Parts Often Needed

Part	Notes
Upper oven thermistor / oven temperature sensor	Amazon \| OEM LG part matched to your range model number. The most common F1 repair.
Oven sensor wiring harness	Amazon \| If the factory harness is burned, pinched, or has damaged connectors that cannot be repaired.
Main control board (ERC)	Amazon \| Electronic range control assembly. Replace only after confirming the sensor and wiring test good but F1 remains.

When to Call a Pro

Call a technician if you are not comfortable working inside a live appliance circuit, if you do not have a multimeter and the skills to safely test the thermistor, or if the F1 code returns after you have replaced the sensor and verified all wiring. A qualified appliance repair tech can quickly isolate whether the fault is in the sensor, harness, or control board and has access to OEM diagnostics and the correct replacement parts for your specific LG range model.