How do I fix error code F-9 on a LG ovens & ranges?

1. undefined: Check if the connector is disconnected or loose — check electric wiring of Relay PCB all taps and electric wiring of electric elements. If loose or disconnected, reconnect; if harness is defective, replace or fix. 2. undefined: Unplug the unit and measure resistance of each heater after cooling down. Normal values: Broil heater ≈ 13.5Ω, Convection heater ≈ 23Ω. Check at pins 5 and 6 of CN6 in Main PCB. If not normal, replace the failed heater. 3. undefined: Check thermistor resistance — normal = approximately 1.09 kΩ at 25°C (checked at pins 5 and 6 of CN6 of Main PCB). If abnormal, replace the defective thermistor. 4. undefined: Plug in unit and enter test mode (press any button with Mode knob in Off, then press '4' and '6' simultaneously for 1 second, then press '4' and '6' simultaneously for 1 second again). Check thermistor value — normal thermistor value at room temp is 70°F to 90°F. If value is normal, proceed to relay check. 5. undefined: Replace the Relay PCB. If problem persists after Relay PCB replacement, replace the Main PCB.

LG Ovens & Ranges

Error Code F-9

No Heating

Moderate

Address soon - your appliance may not work properly

Also displayed as: F-9

How to Fix

1
Check if the connector is disconnected or loose — check electric wiring of Relay PCB all taps and electric wiring of electric elements. If loose or disconnected, reconnect; if harness is defective, replace or fix.
2
Unplug the unit and measure resistance of each heater after cooling down. Normal values: Broil heater ≈ 13.5Ω, Convection heater ≈ 23Ω. Check at pins 5 and 6 of CN6 in Main PCB. If not normal, replace the failed heater.
3
Check thermistor resistance — normal = approximately 1.09 kΩ at 25°C (checked at pins 5 and 6 of CN6 of Main PCB). If abnormal, replace the defective thermistor.
4
Plug in unit and enter test mode (press any button with Mode knob in Off, then press '4' and '6' simultaneously for 1 second, then press '4' and '6' simultaneously for 1 second again). Check thermistor value — normal thermistor value at room temp is 70°F to 90°F. If value is normal, proceed to relay check.
5
Replace the Relay PCB. If problem persists after Relay PCB replacement, replace the Main PCB.