LG Oven F5 Error — What It Means and Why It Happens
The LG oven F5 error code typically indicates a fault in the oven’s temperature sensing or control/communication system. On many LG electric ranges and wall ovens the F5 code is reported when the control board detects inconsistent temperature feedback, a short or open circuit in the temperature sensor (thermistor/RTD), or failed communication between the user interface and the main electronic control board. Symptoms can include the oven refusing to heat, shutting off unexpectedly, wildly inaccurate temperature readings, extended cooking times, or an error message that prevents normal operation. Left unresolved, the problem can lead to unevenly cooked food, wasted energy, and in rare cases safety risks (overheating or uncontrolled heating) if the thermostat or safety cutouts fail to operate properly.
Common Causes
- Faulty temperature sensor (NTC thermistor / RTD) giving incorrect resistance readings
- Loose or damaged wiring harness/connector between sensor and main board
- Defective electronic control board (main PCB / EOC) or failed components on the board
- Malfunctioning touchpad or user interface sending incorrect commands
- Thermostat or thermal fuse/limit switch tripped or failed
- Power surges or intermittent power causing communication errors
- Cooling fan or relay failure causing overheating/protection triggers
- Corrosion or moisture in connectors or sensor terminals
Troubleshooting Steps
- Power cycle the oven: Turn the range off at the breaker for 60 seconds and restore power. Sometimes transient faults clear and the F5 message will reset.
- Note additional symptoms: Does the oven fail to heat, display other error codes, or make unusual noises? Documenting behavior helps pinpoint the component at fault.
- Inspect visible wiring and connectors: With power off, check the oven sensor connector, harness, and the main control wiring for burns, loose pins, or corrosion.
- Test the oven temperature sensor: Remove the sensor probe and measure resistance with a multimeter at room temperature (typical NTC sensors read ~1000–1100 ohms at 25°C for many models — check your model’s spec). An open circuit or wildly out-of-spec reading suggests replacement.
- Swap or reseat the sensor connector: If the sensor reads correctly but the code persists, reseat connectors and inspect harness continuity. Replace wiring if damaged.
- Check thermal fuse/limit switch: Use a multimeter to test for continuity. A blown thermal fuse will often cause protection faults and must be replaced.
- Reset or recalibrate the control (if available): Some LG ovens have diagnostic modes or calibration options. Consult your model’s service manual to run diagnostics — this can reveal sensor faults or EEPROM errors.
- Inspect the control board: Look for burnt components, swollen capacitors, or visible damage. If the board shows damage or diagnosti