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Error code reference

LG Cooktop Error Code F7

Rear inverter heat sink thermistor fault.

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Rear inverter heat sink thermistor fault.

First step from the service manual

Check connector CN02 on the rear IH module.

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

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What F7 means on a LG cooktop

The F7 error code on an LG induction cooktop indicates a fault in the rear inverter heat sink thermistor. The heat sink thermistor is a temperature-sensing component mounted on the inverter module's heat sink, responsible for monitoring thermal conditions of the power electronics during induction cooking operation. When the control system detects an out-of-range or implausible signal from this thermistor, it triggers the F7 fault and disables the rear cooking zone to prevent damage from undetected overheating.

The rear IH (induction heating) module contains its own inverter circuitry, and the thermistor circuit feeds resistance-based temperature data back to the control board. A properly functioning thermistor will produce a predictable resistance value at a given temperature. If the signal is open, shorted, or outside the expected resistance range, the system interprets this as a sensor fault. Connector CN02 on the rear IH module is the primary interface for this thermistor circuit and is the first point to inspect.

Common causes include a loose or corroded connection at CN02, a failed thermistor, or damage to the wiring harness running between the thermistor and the module. In some cases the rear inverter board itself may be at fault if the connector and thermistor check out correctly. Because this fault involves the inverter's thermal protection circuit, the cooktop will not allow operation of the affected rear zone until the fault is resolved.

Source: manufacturer service documentation.

Common causes of F7

  1. 01

    Loose or disconnected connector at CN02

    Wiring / connection

    The thermistor signal runs through connector CN02 on the rear IH module. Vibration or improper installation can cause this connector to seat incompletely, producing an open-circuit fault. Visually inspect and firmly reseat CN02 as the first diagnostic step.

  2. 02

    Failed rear heat sink thermistor

    Part replacement

    The thermistor itself can fail open or short, sending a signal outside the acceptable resistance range to the control system. Testing the thermistor's resistance value and comparing it to the expected specification will confirm whether the component needs replacement.

  3. 03

    Damaged or pinched wiring harness

    Part replacement

    The wiring between the thermistor and the rear IH module can be damaged by heat, pinching during reassembly, or chafing against metal edges. Inspect the full length of the harness for visible damage, burns, or breaks.

  4. 04

    Corroded or contaminated connector pins

    Wiring / connection

    Moisture or grease contamination at the CN02 connector can increase contact resistance enough to produce a false fault reading. Inspect the pins for corrosion or buildup and clean carefully with electrical contact cleaner.

  5. 05

    Failed rear inverter IH module

    Part replacement

    If the connector, wiring, and thermistor all test correctly, the fault may originate within the rear inverter board itself, where the thermistor input circuit has failed. Board replacement would be required in this scenario.

See the test procedure for each cause

Frequently asked questions about F7

What does F7 mean on a LG cooktop?
F7 on an LG cooktop indicates a rear inverter heat sink thermistor fault. The cooktop's control system is not receiving a valid temperature signal from the thermistor mounted on the rear induction module's heat sink. As a result, the rear cooking zone is disabled until the fault is corrected. The first place to check is connector CN02 on the rear IH module.
Can I fix the F7 error myself?
Some cases of F7 can be resolved by a knowledgeable DIYer, particularly if the cause is simply a loose connector at CN02 on the rear IH module. However, if the thermistor itself or the inverter board needs replacement, the repair involves working with high-voltage induction electronics and should be handled by a qualified technician. Always disconnect power to the cooktop completely before inspecting any internal connections.
Is it safe to keep using my cooktop while F7 is displayed?
When F7 is active, LG's cooktop disables the affected rear cooking zone, so you cannot use that burner. Other zones may remain operational, but it is best to have the fault diagnosed promptly. The thermistor is part of the thermal protection system, so operating the unit with a known sensor fault is not advisable.
Will resetting the cooktop clear the F7 error?
Cycling power to the cooktop may temporarily clear the F7 display, but the fault will return if the underlying issue with the rear heat sink thermistor or its wiring is not corrected. A reset does not repair a failed thermistor, damaged wiring, or a faulty connection at CN02. Proper diagnosis and repair are needed for a lasting resolution.
How much does it cost to repair an F7 error on an LG cooktop?
Repair costs depend on the root cause. If only the connector needs reseating, the cost is minimal, primarily a service call fee ranging from roughly $75 to $150. Thermistor replacement parts are generally inexpensive, though labor adds to the total. If the rear inverter IH module requires replacement, parts and labor combined could range from $200 to $450 or more depending on the specific model and your location.

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