LG Oven Error Code F3: Troubleshooting and Calibration... | appliancefaults.com

Technical Background:

The F3 error code on an LG oven typically indicates a problem with the oven temperature sensor circuit. The Main Control Unit (MCU) monitors the voltage signal from the sensor. If the voltage is out of range (either too high or too low), the MCU interprets this as a fault and displays the F3 error code. The sensor voltage is related to the temperature of the oven cavity. The MCU compares this to the desired temperature. There are voltage dividers and A/D converters on the board that translate sensor resistance to a digital reading the MCU can interpret.

Symptoms:

The oven displays an F3 error code. The oven may not heat properly, may overheat, or may not maintain the set temperature. The oven may shut off during operation.

Possible Causes:

Faulty oven temperature sensor (RTD or Thermistor).
Wiring harness issues between the sensor and the control board.
Defective oven control board (MCU).
Oven over temperature condition.
Calibration error.

Solution:

1

Disconnect power to the oven at the breaker panel (LOTO).
2

Locate the oven temperature sensor inside the oven cavity, usually at the rear.
3

Disconnect the sensor wires from the control board. Use a multimeter to measure the resistance of the sensor. Refer to the LG service manual for the correct resistance value at room temperature (typically around 1080 ohms at 77°F).
4

Inspect the wiring harness between the sensor and the control board for any signs of damage or loose connections.
5

If the sensor resistance is out of range, replace the sensor.
6

If the wiring harness is damaged, repair or replace it.
7

If the sensor and wiring are good, the control board may be faulty. Replace the control board. (Consider calling a licensed technician at this point).

Safety Warning:

Disconnect power to the oven at the breaker panel before performing any repairs. This is a Lock Out Tag Out (LOTO) procedure. The oven contains high voltage components that can cause serious injury or death. If you are not comfortable working with electricity, consult a qualified appliance repair technician.

Prevention:

Regularly inspect the oven cavity for any signs of damage to the temperature sensor or wiring. Avoid using harsh chemicals or abrasive cleaners inside the oven, as they can damage the sensor. Check the oven vent for blockage.

Expert Tip:

Many LG ovens have a calibration feature in the service menu. Access the service menu and check the calibration setting. Adjust the calibration if necessary, following the instructions in the service manual. The service menu is often accessed by pressing and holding two specific buttons simultaneously for several seconds (consult the tech sheet).

Frequently Asked Questions

•What is the typical resistance range for an LG oven temperature sensor at room temperature?

The typical resistance range for an LG oven temperature sensor at room temperature (around 77°F) is usually around 1080 ohms, but always refer to the specific service manual for your model to confirm this value.

•How do I access the service menu to calibrate the oven temperature on my LG oven?

Accessing the service menu varies depending on the model. Consult the technical data sheet taped to the back of the unit. The most common sequence is holding down the 'Oven' and 'Start' buttons simultaneously for 5 seconds. Be very careful navigating this menu as you can affect other systems.

•If the sensor tests good and the wiring looks fine, is it safe to assume the control board is the problem?

Not necessarily. While a faulty control board is a possibility, it's crucial to rule out other potential issues like a faulty connection at the control board or a software glitch before replacing the control board. Check the voltage to the sensor is correct and verify the bake and broil elements are not grounding out which can also trigger F3.

LG Oven Error Code F3: Troubleshooting and Calibration Guide

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip:

Frequently Asked Questions

•What is the typical resistance range for an LG oven temperature sensor at room temperature?

•How do I access the service menu to calibrate the oven temperature on my LG oven?

•If the sensor tests good and the wiring looks fine, is it safe to assume the control board is the problem?

Related questions

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip: