LG Oven Error Code F3

LG oven F3 error is a common fault code that typically points to a temperature sensing or communication problem inside the oven. When the control system detects a reading from the oven temperature sensor (NTC thermistor) that is out of expected range — open, shorted, or inconsistent — it will display F3 and may stop normal heating or put the oven into a fault state. The practical impacts for users include inaccurate cooking temperatures, longer or uneven cook times, oven not heating at all, unexpected shutoffs, and in some cases a potential safety concern if the appliance cannot reliably monitor its temperature.

Common causes

• Faulty oven temperature sensor (NTC thermistor) — open, shorted, or drifting out of spec
• Loose, corroded, or damaged wiring harness or connector between sensor and control board
• Damaged or failing main control board (electronic control / PCB) misreading the sensor
• Burnt or loose terminal connections where the sensor plugs into the control board
• Heat damage to the sensor or harness from heavy use, spills, or physical impact
• High-limit thermostat or thermal fuse triggering or failing (less common but possible)
• Software/firmware glitch (rare) or incorrect diagnostics from the control board

Troubleshooting steps

1. Power safety first: Turn the oven off and disconnect power at the circuit breaker before inspecting or attempting any repairs.
2. Reset and re-test: Turn power off for 60 seconds, restore power and see if F3 returns. Temporary resets can clear intermittent faults.
3. Visual inspection: Open the oven and inspect the temperature sensor (usually on the back wall), wiring and plug for obvious damage, burn marks, pin corrosion or loose connections.
4. Access the sensor: Remove the screws securing the sensor probe to the oven cavity and gently pull it out to expose the connector (refer to your model’s service manual).
5. Measure sensor resistance: With the sensor disconnected and cold (room temperature), measure resistance with a multimeter. Typical NTC oven sensors read roughly 1,000–1,200 ohms at ~25°C (check your model’s spec). An open circuit (infinite) or near-zero indicates a bad sensor.
6. Check wiring continuity: Test continuity from the sensor connector to the control board connector. Repair or replace any damaged wires or connectors.
7. Swap or test the sensor: If you have a known-good sensor or can temporarily replace it, that’s a quick way to confirm the diagnosis.
8. Inspect control board: If the sensor and harness test good, inspect the control board for burnt components, swollen capacitors, or damaged terminals. Boards can fail and misread sensors.
9. Replace the failed component: Replace the sensor, harness, or control board as indicated by your tests. Use OEM parts where possible to ensure accuracy and longevity.
10. Final test: Reassemble, restore power, and run a bake cycle or self-test per the owner’s manual to verify the F3 code no longer appears and the oven reaches set temperatures.

Maintenance / Prevention Tips

• Keep the oven interior clean — grease and food debris can overheat and damage sensors or wiring.
• Avoid hitting or bending the temperature sensor when loading pans; it’s a delicate probe.
• Use oven-safe cookware and avoid placing items directly against the sensor probe.
• Inspect the sensor and wiring visually every 6–12 months for wear or heat damage.
• Replace discolored or brittle wiring as soon as it’s noticed to prevent shorts.
• Use a door gasket in good condition to maintain correct internal temperatures and reduce sensor stress.
• Don’t use abrasive cleaners on or near the sensor; use mild detergents and soft cloths.
• Allow the oven to cool before cleaning the sensor area to prevent thermal shock.
• When sliding heavy racks, avoid scraping the back wall where the sensor is mounted.
• Schedule periodic professional tune-ups if you use the oven heavily (commercial-style use at home).
• Address small faults early — intermittent codes often precede full sensor failure.
• Use the correct replacement parts (OEM sensors and connectors) to maintain calibration.
• Keep model and serial numbers handy — technicians will diagnose faster with correct info.
• Consider using an appliance surge protector to protect the control board from power spikes.

FAQs

Conclusion / Safety Notice

Diagnosing and repairing an F3 error often involves working near electrical connections and interior oven components. Always disconnect power at the breaker before attempting inspections or repairs. If troubleshooting points to a failed control board, complex wiring faults, or if you’re unsure how to safely proceed, contact a qualified appliance technician. Improper repairs can cause further damage or safety hazards.

When in doubt, choose safety: stop using the oven until the issue is resolved and call an authorized LG service provider or licensed appliance repair technician to ensure correct, safe repairs.