LG Oven F3 Error Code: Open Temp Sensor Fix

What is the LG Oven F3 error?#

F3 on an LG oven means the temperature sensor circuit is open — the sensor has failed, disconnected, or its wiring is damaged, so the board has no valid temperature to work with and will not heat. It is not a fire risk like an over-temp fault; the oven simply refuses to bake. The most common cause is the sensor itself failing open or coming loose, so the first thing I check is whether F3 appears the moment you select bake.

F3 on a LG Oven: likely causes and repair cost#

On a LG Oven, the F3 code signals: open oven temp sensor.

Typical professional repair: $120–$230 · Difficulty: moderate · usually a technician job

Symptoms that often accompany F3: Oven will not heat at all; F3 error appears immediately when bake is selected; Oven temperature wildly inaccurate; Error appears only after oven heats up for a while

Technician diagnostic sequence for F3:

1. Verify the oven temperature sensor (RTD probe) is securely mounted in the rear wall of the oven cavity — the mounting screws may have loosened from thermal expansion cycling
2. Check the sensor wire connection at the control board — pull the oven away from the wall and access the rear panel to locate the sensor connector
3. Test the sensor resistance from the control board connector (disconnect it first) — at room temperature expect approximately 1080 ohms; open circuit confirms a broken sensor or wire
4. Trace the sensor wiring for breaks, especially where it passes through the oven insulation and the cabinet rear wall — thermal cycling can fatigue the copper conductors
5. If the wiring is intact, flex the sensor wire gently while monitoring resistance — an intermittent open indicates a fractured conductor inside the insulation

Parts a technician may check or replace: Temperature Sensor/RTD Probe; Sensor Wire Harness

Field note: LG oven temperature sensors use RTD (Resistance Temperature Detector) technology, not thermistors. The resistance increases linearly with temperature: approximately 1080 ohms at 77F, 1300 ohms at 350F, 1500 ohms at 550F. A sensor reading that is correct at room temp but open at operating temperature has a hairline crack in the platinum element.

How to troubleshoot the F3 error yourself#

F3 leaves an owner one useful reset before it becomes a service call. Cut power at the breaker for about five minutes, then restore it and select bake — if F3 was a momentary read error, it clears. If F3 appears immediately every time you start the oven, the sensor circuit is open. If you can see the sensor probe inside the oven at the rear, confirm it is not obviously dislodged from its bracket or melted, but do not start pulling wiring. Beyond that, the diagnosis belongs to a technician. Stop and call one if F3 persists: the temperature sensor probe or its wire harness has to be metered — an open sensor reads as no connection — and replaced, which means accessing the sensor and its harness behind the oven.

Is the LG Oven F3 error worth fixing?#

F3 is one of the more affordable LG oven repairs and is well worth fixing. A professional job runs $120–$230 to replace the temperature sensor probe and, if damaged, the sensor wire harness — a small figure against a new range and far below half its price. A sensor swap does not approach my repair-or-replace line. The only time I raise replacement is on an old oven where the sensor fault is one of several problems that together outweigh the value of the appliance.

LG Oven F3: frequently asked questions#

What does the F3 error mean on a LG Oven?#

F3 means the temperature sensor circuit is open — the sensor has failed, disconnected, or its wiring is damaged. Without a valid temperature, the oven will not heat and posts F3.

Is it safe to keep using a LG Oven that shows the F3 error?#

It is not a hazard, but the oven will not heat, so it is unusable for baking. There is no danger in leaving it powered while you arrange a repair.

Can I clear the F3 error myself, or do I need a technician?#

You can try a five-minute power reset. If F3 returns as soon as you select bake, the sensor or its wiring is open and needs a technician to meter and replace.

How much does it cost to repair the F3 error on a LG Oven?#

A professional F3 repair typically runs $120–$230, covering the temperature sensor probe and, if damaged, the sensor wire harness.

Which parts usually fail when a oven throws the F3 code?#

The temperature sensor probe failing open is the usual cause, followed by a disconnected or damaged sensor wire harness.

Is a LG Oven with the F3 error worth repairing?#

Yes. At $120–$230 it is one of the cheaper oven repairs, so unless the range is failing elsewhere, fixing F3 is the sensible choice.

Why does sensor disconnected trigger the F3 error?#

The board reads the sensor as a resistance that changes with temperature. When the sensor opens or unplugs, the board sees an infinite, invalid reading and posts F3, refusing to heat without a trustworthy temperature.