LG Oven F2: Over-Temperature Detected

F2 means the oven temperature sensor (RTD probe) reported a temperature exceeding the maximum safe limit — typically above 650 degrees F during normal baking (the limit is higher during self-clean, approximately 950 degrees F). The board shuts off all heating elements and displays F2 as a safety action.

How the Oven Monitors Temperature

LG ovens use an RTD (Resistance Temperature Detector) sensor — a platinum wire probe mounted inside the oven cavity. Unlike NTC thermistors used in washers and refrigerators, RTD sensors increase resistance as temperature rises. At room temperature, an LG oven RTD reads approximately 1,080-1,100 ohms. At 350 degrees F, it reads approximately 1,600-1,650 ohms. At 550 degrees F, approximately 2,000-2,050 ohms.

The board continuously compares the sensor reading against the programmed maximum for the current operating mode. If the reading exceeds the limit, F2 triggers.

Root Causes

Oven Sensor Failure (40%)

The RTD probe can drift out of calibration, reading higher than actual temperature. A drifted sensor tells the board the oven is 650 degrees F when it is actually 450 degrees F. The board correctly triggers F2 based on the sensor's (incorrect) report.

Alternatively, a partially shorted sensor has lower-than-expected resistance at a given temperature. The board interprets low resistance as low temperature and keeps the element on longer, allowing actual temperature to climb above the setpoint until the secondary thermal limit trips F2.

Relay Sticking (30%)

The bake or broil relay on the ERC board is beginning to weld (contacts sticking closed intermittently). The board commands the element off, the relay sticks for several additional minutes, and temperature climbs past the limit. This is the precursor to F1 — if ignored, the relay will eventually weld permanently.

Door Seal Gap (15%)

The oven door gasket (a braided fiberglass seal around the door perimeter) has gaps or sections that have fallen off. During self-clean, the interior reaches 850-900 degrees F. Hot air escaping through seal gaps can heat the sensor mounting area above the expected range, triggering F2. This also wastes energy and heats the kitchen dangerously.

Ventilation Blocked (10%)

LG ovens vent hot air through a vent tube at the top-rear of the oven body. If this vent is blocked (by a baking sheet stored on top, a towel, or excessive buildup), internal temperature climbs unevenly. The sensor area may overheat while the cooking area is at the correct temperature.

Actual Excessive Temperature (5%)

Rare: the oven is genuinely overheating because the element is receiving power it should not (relay beginning to fail) or the broil element is energizing during bake mode (board logic failure).

Testing the Oven Sensor

1. Turn off the breaker
2. Locate the RTD sensor inside the oven — a metal probe extending from the upper rear wall, held by 1-2 screws, with a 2-wire connector accessible from the rear
3. Disconnect the sensor connector
4. Measure resistance at room temperature: expect 1,080-1,100 ohms
5. If significantly higher (above 1,200 ohms at room temp) or infinite: sensor is failed or drifted. Replace
6. If significantly lower (below 900 ohms at room temp) or near zero: sensor is shorted. Replace

Sensor Replacement

1. Breaker off
2. Inside the oven, remove the 1-2 screws holding the sensor probe bracket to the rear wall
3. Pull the sensor out through the rear wall. The wire connector is accessible from the rear of the oven
4. Disconnect the old sensor. Connect the new sensor (MEG52785806 or model-specific, $15-30)
5. Push the probe through the rear wall into the cavity. Secure with screws
6. Restore power. Run a bake test at 350 degrees F — verify F2 does not return and the oven holds the correct temperature (verify with an oven thermometer)

Parts and Cost

F2 During Self-Clean

Self-clean cycles intentionally reach 850-900 degrees F. F2 during self-clean means the temperature exceeded even the elevated self-clean limit. This usually indicates a door seal gap (hot air escaping disrupts the sensor area's expected temperature profile) or a sensor that is drifted enough to read over-range at self-clean temperatures but within range at normal baking temperatures.

F2 vs. F3

F2 means over-temperature (too hot). F3 means the sensor circuit is open or shorted (no reading at all). F2 implies the sensor is working but reporting high. F3 implies the sensor is broken. Both involve the same sensor component but represent different failure modes.

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LG oven overheating or showing F2? We test the RTD sensor with calibrated instruments and check relay health. Book temperature diagnosis.