How to Replace the Oven Temperature Sensor on an LG Range

The oven temperature sensor (RTD probe or thermistor) in LG ranges monitors cavity temperature and reports it to the control board, which uses this reading to cycle heating elements on and off to maintain the set temperature. When the sensor fails, common symptoms include oven not heating (F9 or similar error code), oven overheating (sensor reading low, so board keeps heating), or significant temperature inaccuracy. LG ovens including ProBake Convection models use a single sensor mounted at the upper rear of the oven cavity.

This guide covers temperature sensor replacement on LG freestanding ranges, slide-in ranges, and wall ovens. The sensor is a thin metal probe approximately 5-7 inches long that protrudes into the oven cavity from the upper rear wall. It is one of the simplest oven repairs because it involves only one mounting screw and one wire connector.

Before You Start

• Tools needed: Phillips #2 screwdriver, multimeter (for testing), work gloves
• Parts needed: LG oven temperature sensor for your model (~$15-$30)
• Time required: 10-15 minutes
• Difficulty: Beginner
• Safety warning: Turn off the oven and allow it to cool completely. Disconnect power by unplugging or turning off the breaker. The sensor itself carries no dangerous voltage, but the wire harness connects to the control board which is powered by 120V.

Step-by-Step Instructions

Step 1: Test the Existing Sensor

Before replacing, confirm the sensor is the problem. Disconnect power. Access the sensor wire connector either inside the oven (follow the probe to where it exits the rear wall) or from behind the range (rear panel access to wire junction). Set multimeter to resistance. At room temperature (70 degrees F), a healthy LG oven sensor reads approximately 1080-1100 ohms. Significantly different readings (OL, 0 ohms, or wildly off from 1090) confirm sensor failure.

Step 2: Locate the Sensor Inside the Oven

Open the oven door. The temperature sensor probe extends from the upper rear wall of the oven cavity, typically in the upper-left or upper-center area. It is a thin metal tube, approximately 1/4 inch diameter, mounted with a single screw at its base bracket where it enters the wall. On LG ProBake models, do not confuse the sensor with the meat probe receptacle (if equipped), which is located at a different position.

Step 3: Remove the Mounting Screw

Remove the single Phillips screw holding the sensor bracket to the inside of the oven rear wall. The sensor probe is now free to be pulled through the wall. On some LG models, there is also a small retaining clip that must be squeezed before the sensor slides out.

Step 4: Pull the Sensor Through the Wall

Gently pull the sensor probe forward and out of the rear wall. The sensor wire follows it through a rubber grommet in the wall. From outside (rear of range), disconnect the wire connector. On most LG models, this is a 2-pin plug connector near where the wire exits the rear of the oven cavity. Press the locking tab and pull apart.

Step 5: Connect the New Sensor Wire

Plug the new sensor's wire connector into the same junction point. The connector is keyed and only fits one way. Push until the locking tab clicks.

Step 6: Feed the New Sensor Through the Wall

From outside the oven, feed the new sensor probe through the grommet hole into the oven cavity. From inside, pull the probe through until the mounting bracket sits flush against the wall.

Step 7: Secure with Mounting Screw

Reinstall the Phillips screw through the sensor bracket into the oven wall. The sensor probe should extend horizontally into the oven cavity without contacting racks, walls, or food. It should be positioned away from direct element radiation (not directly in front of or above a heating element) for accurate ambient temperature reading.

Step 8: Test and Calibrate

Restore power. Set oven to 350 degrees F. Use an independent oven thermometer placed in the center of the middle rack to verify accuracy. LG ovens allow temperature calibration offset through the control panel (typically accessed by pressing and holding the Bake button or through settings menu). Adjust by +-5 degree increments until the oven thermometer matches the set temperature. Allow 20-30 minutes of stable operation before calibrating.

Troubleshooting Common Issues

• If the oven still displays a temperature error code after sensor replacement, perform a hard reset (unplug 5 minutes). The control board may need to clear the stored error. If the code persists, the control board itself may have a fault in the sensor reading circuit
• If the oven overheats after sensor replacement, verify the new sensor resistance matches specification at room temperature before installation (1080-1100 ohms at 70F). An incorrect sensor value causes the board to misread temperature
• If temperature is consistently off by the same amount, use the built-in calibration offset rather than replacing the sensor again. Sensor-to-sensor manufacturing variation can account for 5-15 degree differences
• If the sensor wire is too short to reach the connector on the new part, do not splice. Order the correct model-specific sensor with the proper wire length
• On LG ProBake models, verify EasyClean and self-clean modes reach their target temperatures after sensor replacement. These modes rely on accurate sensor feedback to control cycle duration and door lock timing

When to Call a Professional

• If error codes persist after sensor replacement and reset, the control board's sensor input circuit may need professional diagnosis
• If the oven consistently reads wrong temperatures and calibration offset cannot compensate, a second independent problem (failing element, insulation issue, or board malfunction) may exist
• If the wire grommet in the oven rear wall is damaged or missing, oven heat can escape to the wiring area behind. Professional gasket or grommet replacement ensures proper thermal isolation

Cost Comparison: DIY vs Professional

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FAQ

Q: What resistance should my LG oven temperature sensor read? A: At room temperature (approximately 70 degrees F), a healthy LG oven sensor reads 1080-1100 ohms. Resistance increases as temperature rises. If your reading at room temp is significantly different (more than 10% off), the sensor has failed.

Q: Can a bad temperature sensor cause my LG oven to overheat? A: Yes. If the sensor reads lower than actual temperature (low resistance fault), the control board believes the oven is cooler than it is and continues heating. This can cause the oven to exceed set temperature significantly. Replace immediately if overheating occurs.

Q: Is the temperature sensor the same as the meat probe? A: No. The temperature sensor is permanently mounted in the oven wall and measures air temperature. The meat probe (if equipped) is a removable accessory that plugs into a receptacle on the side wall and measures internal food temperature.

Q: How do I calibrate my LG oven temperature after sensor replacement? A: Use an oven thermometer to determine the offset. Access calibration through the control panel (hold Bake or navigate Settings). Adjust in 5-degree increments until oven thermometer matches set temperature. Allow 30 minutes stable operation before each adjustment.

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