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Error code reference

LG Cooktop Error Code F2

Front left inverter heat sink thermistor fault.

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Front left inverter heat sink thermistor fault.

First step from the service manual

Check connector CN02 on the front IH module.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What F2 means on a LG cooktop

The F2 error code on an LG induction cooktop indicates a fault in the heat sink thermistor located within the front left inverter IH (induction heating) module. The heat sink thermistor is a temperature-sensing component that monitors the thermal state of the inverter's heat sink, which dissipates heat generated by the high-frequency switching components in the induction circuit. When the control system detects that the thermistor is sending a reading outside of its expected resistance range, either due to an open circuit, a short, or a sensor failure, it triggers the F2 fault and disables the front left cooking zone to prevent damage.

The inverter module drives the induction coil by converting DC voltage into high-frequency AC current. Managing heat in this module is critical because excessive temperatures can destroy the IGBT transistors and other power components. The thermistor feeds real-time temperature data to the control board, allowing the system to throttle power or shut down if temperatures rise too high. A failed or disconnected thermistor removes this safety feedback loop entirely, prompting the F2 code as a protective response.

The first diagnostic step is to inspect connector CN02 on the front IH module. A loose, corroded, or damaged connector at this point is a common cause of the fault and should be checked before assuming the thermistor or module itself has failed. If the connector is secure and undamaged, the thermistor's resistance should be measured and compared against the expected specification, and the wiring harness between the connector and the control board should be inspected for breaks or shorts.

Source: manufacturer service documentation.

Common causes of F2

  1. 01

    Loose or disconnected connector CN02

    Wiring / connection

    The connector CN02 on the front IH module can work loose over time due to vibration or thermal cycling. This is the first component to inspect, as a poor connection will cause the control board to read an invalid thermistor signal and trigger F2.

  2. 02

    Failed heat sink thermistor

    Part replacement

    The thermistor itself can fail open or short out, producing a resistance reading outside the expected range. This will consistently trigger F2 regardless of connector condition and requires replacement of the thermistor or the IH module assembly.

  3. 03

    Damaged wiring harness

    Part replacement

    The wiring between connector CN02 and the main control board can suffer from chafing, heat damage, or breaks. Inspect the full length of the harness for any visible damage, pinching, or melted insulation.

  4. 04

    Corroded connector pins

    Wiring / connection

    Moisture or grease contamination at connector CN02 can cause corrosion on the pins, increasing resistance in the thermistor circuit and producing false or erratic readings. Clean or replace the connector if corrosion is present.

  5. 05

    Faulty front IH inverter module

    Part replacement

    If the thermistor, connector, and wiring all test correctly, the front IH inverter module itself may have an internal fault affecting the thermistor circuit. Replacement of the module would be required in this case.

See the test procedure for each cause

Frequently asked questions about F2

What does F2 mean on a LG cooktop?
The F2 code on an LG induction cooktop indicates a fault with the heat sink thermistor in the front left inverter IH module. The thermistor monitors temperature inside the induction electronics, and when its signal falls outside the expected range, the cooktop disables the front left zone and displays F2. The first step in diagnosing this error is checking connector CN02 on the front IH module for a loose or damaged connection.
Can I fix the F2 error on my LG cooktop myself?
A knowledgeable DIYer can attempt to resolve F2 by carefully inspecting and reseating connector CN02 on the front IH module, since a loose connection is the most common cause. However, if the thermistor, wiring harness, or inverter module needs replacement, the repair involves working near high-voltage induction components, which carries a significant safety risk. It is strongly recommended to have a qualified appliance technician perform any repairs beyond the initial connector inspection.
Is it safe to keep using my LG cooktop when it shows F2?
When F2 is active, the cooktop disables the front left cooking zone as a protective measure, meaning that zone will not operate. While the remaining zones may still function, it is not advisable to continue using the appliance with an active fault code. The thermistor failure removes a key thermal protection safeguard, and continued use without repair could risk damage to the inverter module components.
Will resetting my LG cooktop clear the F2 error?
Powering the cooktop off and back on may temporarily clear the F2 display, but the error will return if the underlying fault with the thermistor circuit is still present. A reset does not repair a failed thermistor, damaged wiring, or a faulty connector. The code will continue to appear until the root cause is diagnosed and corrected.
How much does it cost to repair an F2 error on an LG cooktop?
Repair costs vary depending on what component has failed. If only the connector needs reseating or cleaning, the cost may be limited to a service call fee, typically in the range of $75 to $150. If the thermistor or the front IH inverter module requires replacement, parts and labor combined can range from $150 to $400 or more depending on parts availability and local labor rates.

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