By going through these solutions, you’ll gain a better understanding of the error codes that may appear on your LG microwave. Keep in mind that just because an error code is displayed doesn’t necessarily mean the corresponding component is faulty.
Before replacing any components, it’s important to check the connections of the wiring and eliminate any potential connection issues.
LG Microwave Common Error Codes
Remember to always unplug the microwave and exercise caution when attempting any repairs.
E-01: Thermistor short error
This error indicates that the overheating safety device is not detected within four seconds after starting any cooking program.
Related error codes:
- F-02: Thermistor short error
- F-1: Thermistor open error
- F-2: Thermistor short error
Causes:
- Damaged wire harness
- Faulty thermistor
- Faulty main board
Solutions:
- Check the wire harness connector.
- Check the thermistor resistance.
| Electric part name | Temperature | Ohmic value |
|---|---|---|
| Thermistor | 25°C/77°F | ~ 1.2 KΩ |
- Check the main board.
E-02: Low temperature error
This error indicates that the inner temperature is not above 100°C within ten minutes after starting the convection cooking program.
Related error code:
- F-01: Temperature-low error
Causes:
- Faulty thermistor
- Faulty heating element
- Faulty main board
Solutions:
- Check the thermistor.
| Electric part name | Temperature | Ohmic value |
|---|---|---|
| Thermistor | 25°C/77°F | ~ 1.2 KΩ |
- Check the heater assembly.
| Heater Assy. | Upper sheath | Lower sheath | Upper Halogen | Upper Ceramic |
|---|---|---|---|---|
| Ohmic value | ~ 48 Ω | ~ 75 Ω | ~ 2.8 Ω | ~ 28 Ω |
- Check the main board.
E-03: Fan relay shorted error
This error indicates that the inner temperature is not below 100°C within thirty minutes after the end of the cooking program.
Related error code:
- F-13: Fan relay error
Causes:
- Faulty fan motor
- Faulty fan relay
- Faulty main board
Solutions:
- Check the fan motor wire harness connection.
- Check the fan motor.
| Fan motor | Low-speed coil | high-speed coil |
|---|---|---|
| Ohmic value | ~ 115 Ω | ~ 28 Ω |
- Check the fan relay.
- Check the main board.
E-04: Preheat error
This error indicates that the inner temperature is not above 100°C within three minutes after starting the preheating process.
Related error code:
E-05: Fermentation mode error indicates that the inner temperature was above 70°C for more than four seconds during the fermentation program.
Causes:
- Faulty thermostat
- Faulty thermistor
- Faulty heater
- Faulty main board
Solutions:
- Check the thermostat.
| Thermostat | Microwave | MAGNETRON |
|---|---|---|
| Temperature | 155°C | 311°F | 140°C | 284°F |
| Ohmic value | ~ 0.1 – 1.2 Ω | ~ 0.1 – 1.2 Ω |
- Check the thermistor.
| Electric part name | Temperature | Ohmic value |
|---|---|---|
| Thermistor | 25°C/77°F | ~ 1.2 KΩ |
- Check the heater assembly resistance.
| Heater Assy. | Upper sheath | Lower sheath | Upper Halogen | Upper Ceramic |
|---|---|---|---|---|
| Ohmic value | ~ 48 Ω | ~ 75 Ω | ~ 2.8 Ω | ~ 28 Ω |
- Check the main board.
E-10: Short Keypad error
This error indicates that communication between the keypad and the controller is blocked.
Related error codes:
- F-3: Short button error.
- F-10: Key error.
Causes:
- Faulty control board.
- Faulty main board
Solutions:
- Check and replace, if necessary, the control panel.
- Check and replace, if necessary, the main board.
F-11: Inverter communication error
This error indicates that communication between the inverter board and the main board is blocked.
Causes:
- Faulty wire harness cable
- Faulty Inverter board
- Faulty main board
Solutions:
- Check the harness between the inverter board and main board.
- Check and replace, if necessary, the inverter board.
- Check and replace, if necessary, the main board.
F-13: Inverter overcurrent
Related error codes:
- F-14: Inverter over voltage
- F-15: Inverter under voltage
- F-19: Inverter VDC protection
Causes:
- Damaged wire harness
- Faulty fan motor
- Faulty inverter Magneton
- Faulty inverter board
- Faulty main board
Solutions:
- Check the harness between the inverter and main board.
- Check the fan motor.
- Check MAGNETRON status: magnet crack, antenna, and/or gasket burnt mark.
- Check and replace, if necessary, the inverter board.
- Check and replace, if necessary, the main board.
F-16: Inverter heat sink error
Causes:
- Faulty wire harness
- Faulty fan motor
- Faulty inverter board
- Faulty main board
Solutions:
- Check the harness between the inverter and main board.
- Check the fan motor.
- Check and replace, if necessary, the inverter board.
- Check and replace, if necessary, the main board.
F-17: Inverter temperature sensor error
Causes:
- Faulty wire harness
- Faulty TH91 thermistor
- Faulty inverter board
Solutions:
- Check the harness between the inverter and main board.
- Check the TH91 sensor resistance using a multimeter.
| Electric part name | Temperature | Ohmic value |
|---|---|---|
| TH91 sensor | 23°C/73°F | ~ 18.2 KΩ |
- Check and replace, if necessary, the inverter board.
F-4: Humidity sensor error
This error indicates that the humidity sensor is not detected within four seconds after starting any cooking program.
Causes:
- Faulty wire harness
- Faulty humidity thermostat
- Faulty main board
Solutions:
- Check the harness between the inverter and main board.
- Check the humidity sensor resistance using a multimeter.
- Check and replace, if necessary, the main board.
COOL: Cooling down notification
The COOL error is a notification that the program is finished. Explain that the fan will operate until the temperature of the inverter unit has dropped.
Loc: Child lock notification
Loc is a notification that the control panel is locked, which prevents the appliance from being turned on when cleaning and/or unsupervised children from using the microwave. To deactivate Loc notification, press and hold the Stop/Clear button for 3 seconds, and then the last program will appear on the display to indicate that the child lock has been deactivated successfully.
DOOR: Door lock error
The door error indicates a problem with the door lock system not closing the power circuit loop.
Causes:
- Open door after program starts
- Not completely closed door
- Faulty door interlock
- Faulty main board
Solutions:
- Check the microswitch’s wire harness connectors.
- Check the door lock assembly.
- Check the main board.
Conclusion:
Understanding error codes that may appear on your LG microwave oven can help you troubleshoot and fix any issues that may arise. However, it’s important to remember that the display of an error code does not automatically mean that the corresponding component is faulty. It is necessary to check the connections of the wiring and eliminate any potential connection problems before replacing any components.
I am a master Appliance Repair technician with over 35 years of experience in the field. I am passionate about helping people troubleshoot their appliances and fix common problems. My website, appliancemode.com, provides a wealth of information on troubleshooting common appliance issues and deciphering error codes. This website aims to empower people to tackle appliance repairs themselves and save money on service calls.
