LG Range Oven Error Codes Explained: Expert Troubleshooting Guide

When your LG range or wall oven displays an error code, it is alerting you to a specific system fault detected by the electronic control board. These fault codes are designed to help homeowners and technicians quickly identify problems related to temperature sensors, heating circuits, door lock mechanisms, cooling fans, communication systems, and other critical oven components.

Understanding what the LG range oven error codes mean can save valuable diagnostic time and help determine whether the issue is something simple, such as a loose connection, or a more serious component failure requiring replacement.

LG Range Oven Error Codes

Important Safety Warning

Before performing any inspection, troubleshooting, or repair:

• Disconnect power to the appliance at the circuit breaker.
• Allow all oven surfaces and heating elements to cool completely.
• Use proper electrical safety precautions when testing components.
• If you are not comfortable working with live electrical systems, contact a qualified appliance repair technician.

Many LG range error codes involve high-voltage circuits, heating elements, relays, and electronic control boards that can present electrical shock hazards if handled improperly.

How LG Range Oven Diagnostics Work

Modern LG ovens continuously monitor critical components through sensors and feedback circuits. When the main control board detects an abnormal condition, it stores a fault code and may disable heating functions to prevent damage or unsafe operation.

Commonly monitored components include:

• Oven temperature sensors (thermistors)
• Bake and broil heating elements
• Convection fan motors
• Cooling fans
• Door lock assemblies
• Meat probe sensors
• Communication circuits
• Main control boards

Most LG range fault codes begin with the letter “F”, followed by a number that identifies the affected system.

LG Oven Temperature Sensor Error Codes

Temperature sensor failures are among the most common LG oven problems. The control board relies on accurate thermistor readings to regulate cooking temperatures. An open, shorted, or inaccurate sensor can trigger fault codes and prevent normal operation.

F1: Upper Oven Sensor Open

Fault Description

The main control board has detected an open circuit in the upper oven temperature sensor circuit and can no longer monitor oven temperature accurately.

Common Causes

• Failed upper oven thermistor
• Loose or disconnected sensor connector
• Damaged wiring harness
• Defective electronic control board

Technician Diagnosis

Measure sensor resistance at room temperature. Most LG oven temperature sensors should measure approximately 1,080–1,100 Ω at 77°F (25°C).

Recommended Repair

• Inspect wiring connections
• Test sensor resistance
• Repair damaged wiring
• Replace the sensor if readings are outside specifications

F2: Upper Oven Sensor Shorted

Fault Description

The control board detects a short circuit within the upper oven temperature sensor circuit.

Common Causes

• Shorted thermistor
• Pinched sensor wiring
• Moisture intrusion in connectors

Recommended Repair

Inspect wiring for damage and verify sensor resistance. Replace the sensor if resistance is significantly below specifications.

F4: Lower Oven Sensor Open

Fault Description

An open circuit has been detected in the lower oven temperature sensor circuit.

Possible Causes

• Failed lower oven thermistor
• Broken wire harness
• Poor connector contact
• Control board failure

Recommended Repair

Inspect connections and verify sensor resistance before replacing components.

F5: Lower Oven Sensor Shorted

Fault Description

The lower oven temperature sensor circuit is shorted.

Common Causes

• Damaged thermistor
• Pinched harness
• Connector contamination

Recommended Repair

Inspect wiring and replace the sensor if resistance readings are outside factory specifications.

F8: Meat Probe Short Error

Fault Description

The oven has detected a short circuit in the meat probe circuit.

Common Causes

• Faulty meat probe
• Damaged probe wiring
• Defective probe receptacle

Recommended Repair

Inspect the probe and receptacle for damage and verify resistance values.

LG Oven Heating Error Codes

Heating-related fault codes occur when the control board detects abnormal temperature rise, overheating conditions, or a failure to heat.

F6: Upper Oven Overheat Condition

Fault Description

The upper oven temperature has exceeded safe operating limits.

Common Causes

• Failed temperature sensor
• Welded relay contacts
• Stuck bake or broil relay
• Defective control board

Recommended Repair

Allow the oven to cool completely and test the temperature sensor and relay circuits.

F9: Upper Oven Not Heating

Fault Description

The oven failed to increase temperature during a heating cycle.

Common Causes

• Open bake element
• Failed broil element
• Defective relay
• Faulty sensor
• Wiring failure

Recommended Repair

Verify element continuity and check for proper voltage from the control board.

F16: Lower Oven Overheat Condition

Fault Description

The lower oven temperature exceeded safe operating limits.

Recommended Repair

Inspect the lower oven sensor, heating relays, and electronic control board.

F19: Lower Oven No Heat

Fault Description

The lower oven failed to reach the expected temperature during operation.

Common Causes

• Failed heating element
• Open wiring harness
• Defective sensor
• Faulty control board

Recommended Repair

Test heating elements, sensor resistance, and relay operation.

LG Oven Door Lock Error Codes

Door lock faults typically occur during self-clean cycles when the control board cannot verify proper lock operation.

F10: Upper Door Lock Failure

Common Causes

• Failed door lock motor
• Defective lock switches
• Wiring issues
• Control board failure

Recommended Repair

Inspect the lock assembly and verify motor resistance and switch operation.

F20: Lower Door Lock Failure

Fault Description

The lower oven door lock system failed to operate correctly.

Recommended Repair

Inspect the lock motor, switches, wiring harness, and control board.

LG Communication Error Codes

F11: – Communication Failure

Fault Description

Communication between the main control board and one or more interface boards has been interrupted.

Common Causes

• Loose wiring harness
• Defective display board
• Failed cooktop control board
• Main control board failure

Recommended Repair

Inspect all communication connectors and verify continuity between boards.

LG Convection Fan Error Codes

F7: Upper Convection Fan Error

Fault Description

The upper convection fan failed to operate within expected parameters.

Common Causes

• Failed fan motor
• Damaged wiring
• Defective relay
• Control board failure

Recommended Repair

Check motor resistance and inspect wiring connections.

F17: Lower Convection Fan Error

Fault Description

A malfunction has been detected in the lower convection fan circuit.

Recommended Repair

Test the fan motor, wiring harness, and control board output.

Advanced LG Range Oven Error Codes (F20–F69) Explained

This section covers advanced LG range oven and cooktop error codes related to door lock systems, steam sensors, induction circuits, IGBT modules, fans, and specialty cooking functions such as griddle and sous-vide.

These faults are typically more complex and often require electrical testing, control board diagnostics, and service manual reference.

F20: Lower Oven Door Lock Error

Error Description

The F20 error code indicates a failure in the lower oven door locking system. The control board is unable to confirm proper lock engagement or operation.

Possible Causes

• Faulty wiring harness
• Defective microswitches in the door lock assembly
• Failed door lock motor
• Faulty relay on control board
• Main control board failure

Recommended Troubleshooting

• Inspect the wiring harness connection at the main control board
• Test microswitch operation for continuity
• Check the door lock motor for mechanical or electrical failure
• Inspect relay operation on the control board
• Replace the main control board if all components test correctly

F21/F25: Steam Sensor Circuit Errors

Error Description

These error codes relate to steam system thermistor faults involving open or short circuits in temperature sensors.

• F21: Right steam sensor open circuit
• F22: Right steam sensor short circuit
• F24: Left steam sensor open circuit
• F25: Left steam sensor short circuit

Possible Causes

• Damaged or disconnected wire harness
• Faulty steam thermistor sensor
• Control board failure

Recommended Troubleshooting

• Inspect steam sensor wiring harness connections
• Test sensor resistance with a multimeter
• Verify thermistor reading at room temperature (~25°C / 77°F ≈ 1.09 kΩ)
• Replace faulty sensor or main control board if readings are incorrect

F33/F34: Induction Hob Sensor Errors

Error Description

The F33 and F34 codes indicate faults in the induction cooktop temperature sensing system.

• F33: Front induction hob sensor error
• F34: Rear induction hob sensor error

Possible Causes

• Faulty thermistor sensor
• Damaged wiring harness
• Main control board failure

Recommended Troubleshooting

• Inspect wiring connections between hob and control board
• Test thermistor resistance (~1.09 kΩ at room temperature)
• Replace defective sensor or control board if necessary

F36: IGBT Sensor Error

Error Description

The F36 error indicates a failure in the IGBT temperature monitoring circuit used in induction power control.

Possible Causes

• Faulty IGBT thermistor
• Damaged sensor harness
• Failed inverter board
• Main control board malfunction

Recommended Troubleshooting

• Inspect sensor wiring connections
• Test IGBT thermistor resistance
• Check inverter board functionality
• Replace inverter or main board if required

F38: Induction Communication Error

Error Description

The F38 error occurs when communication between the induction cooktop and control system is interrupted.

Possible Causes

• Loose or damaged communication harness
• Faulty main control board

Recommended Troubleshooting

• Inspect all harness connections between boards
• Verify continuity and secure connections
• Replace main control board if communication cannot be restored

F42: Induction Overvoltage Error

Error Description

The F42 error indicates excessive DC-link voltage detected in the inverter circuit.

Possible Causes

• Faulty induction inverter board
• Main control board failure

Recommended Troubleshooting

• Inspect inverter board for damage
• Check wiring harness integrity
• Replace inverter or control board if overvoltage persists

F45: Box Fan Error

Error Description

The F45 error indicates a malfunction in the oven’s cooling or box fan system.

Possible Causes

• Faulty box fan motor
• Damaged wiring harness
• Faulty cooktop or control board
• Main control board failure

Recommended Troubleshooting

• Inspect fan motor operation
• Check wiring connections
• Test fan voltage supply
• Replace defective fan or control board if needed

F51/F52: Griddle Sensor Errors

Error Description

These codes relate to griddle temperature sensing faults.

• F51: Griddle sensor open circuit
• F52: Griddle sensor short circuit

Possible Causes

• Faulty griddle thermistor
• Wiring harness damage
• Main control board failure

Recommended Troubleshooting

• Inspect wiring connections
• Test sensor resistance (~1.09 kΩ at 25°C / 77°F)
• Replace sensor or control board if readings are abnormal

F56: Griddle Overheat Error

Error Description

The F56 error occurs when the griddle temperature exceeds approximately 345°C (653°F) for an extended period during operation.

Possible Causes

• Faulty thermistor
• Stuck heating relay
• Control board malfunction

Recommended Troubleshooting

• Allow appliance to cool completely
• Inspect temperature sensor accuracy
• Check relay switching operation
• Replace control board if overheating persists

F59: Griddle Heating Failure

Error Description

The F59 error indicates the griddle failed to reach the expected temperature rise within the programmed time.

Possible Causes

• Failed igniter or heating element
• Faulty thermistor
• Wiring or relay failure
• Main control board issue

Recommended Troubleshooting

• Check igniter/heating element operation
• Test thermistor response
• Inspect relay output from control board
• Replace faulty components as needed

F62–F69: Sous-Vide System Errors

Error Description

These codes relate to sous-vide cooking system faults:

• F62: Sous-vide sensor short circuit
• F69: Sous-vide heating failure (no temperature rise)

Possible Causes

• Faulty sous-vide thermistor
• Damaged wiring harness
• Main control board failure

Recommended Troubleshooting

• Replace sensor or control board if readings are incorrect
• Disconnect power before inspection
• Check sensor wiring and connections
• Measure thermistor resistance (~1.09 kΩ at 25°C / 77°F)

General LG Oven Troubleshooting Tips

Before replacing components, perform these basic diagnostic checks:

1. Reset power to the appliance by turning the breaker off for 5 minutes.
2. Verify all wiring harness connections are secure.
3. Inspect connectors for corrosion or heat damage.
4. Test oven temperature sensors for proper resistance.
5. Check heating elements for continuity.
6. Review the technical data sheet for your exact model.

Final Thoughts

LG range oven error codes are valuable diagnostic tools that help identify specific component failures and operating problems. While some issues can be resolved through simple inspections or sensor replacement, others may require advanced electrical testing and professional diagnosis.

Accurately identifying the fault code, testing components systematically, and following manufacturer specifications will significantly improve repair success and prevent unnecessary part replacements.