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Error code reference

LG Range Error Code F3

Key short error

LG codesLG range codes

Key short error — triggered if 25 key short events occur 3 times in 90 seconds, or if communication with the Touch IC is impossible for more than 60 seconds.

First step from the service manual

Check wiring and Touch PCB; check connecting states between keypad and CN03 of Main PCB.

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

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What F3 means on a LG range

The F3 error code on an LG range indicates a key short error originating in the touch control system. This fault is triggered under two specific conditions: either 25 individual key short events are detected 3 times within a 90-second window, or communication between the main control board and the Touch IC (integrated circuit) is completely lost for more than 60 consecutive seconds. The Touch IC is the dedicated chip responsible for processing capacitive or resistive input from the keypad and relaying that data to the main PCB. When this communication pathway is disrupted or flooded with erroneous short signals, the control board flags F3 to prevent unintended operation.

The most common hardware path involved is the connection between the keypad, the Touch PCB, and connector CN03 on the main PCB. A damaged or pinched wire harness, a corroded connector pin, or a failed solder joint along this path can interrupt normal signal transmission and produce the fault. In some cases, liquid intrusion beneath the keypad surface creates a persistent short condition across multiple key contacts simultaneously, which can rapidly accumulate the 25-event threshold required to trigger the error.

Diagnosis should begin with a visual inspection of the wiring harness running from the keypad assembly to the Touch PCB, and then from the Touch PCB to the CN03 connector on the main PCB. Check for continuity, signs of heat damage, moisture, or loose connector seating. If the wiring and connectors check out, the Touch PCB itself or the main PCB may require replacement to resolve the fault.

Source: manufacturer service documentation.

Common causes of F3

  1. 01

    Loose or damaged connector at CN03

    Wiring / connection

    The connector joining the Touch PCB signal path to CN03 on the main PCB is a frequent failure point. A loose, corroded, or partially seated connector can disrupt communication entirely or introduce intermittent short signals.

  2. 02

    Liquid intrusion under the keypad

    Part replacement

    Spills or steam that seep beneath the keypad surface can bridge multiple key contacts simultaneously, rapidly generating the short events needed to trigger F3. Inspect the keypad surface and membrane for moisture or residue.

  3. 03

    Failed or damaged Touch PCB

    Part replacement

    The Touch PCB contains the Touch IC responsible for processing keypad inputs. If this board fails due to a component fault, power surge, or physical damage, communication with the main PCB will be lost and F3 will be triggered.

  4. 04

    Damaged wiring harness between keypad and Touch PCB

    Part replacement

    Pinched, burnt, or broken wires in the harness connecting the keypad assembly to the Touch PCB will disrupt signal flow. Look for insulation wear, heat damage near the oven cavity, or chafing against metal edges.

  5. 05

    Failed main PCB

    Part replacement

    If the Touch PCB and all wiring connections test good, the main PCB itself may have a fault preventing it from receiving or interpreting signals through CN03. This is the least common cause but should be considered after other components are ruled out.

See the test procedure for each cause

Frequently asked questions about F3

What does F3 mean on a LG range?
F3 on an LG range indicates a key short error in the touch control system. It is triggered when 25 key short events occur 3 times within 90 seconds, or when communication between the Touch IC and the main PCB is lost for more than 60 seconds. The fault points to the keypad, Touch PCB, or the wiring and connectors linking those components to connector CN03 on the main control board.
Can I fix the F3 error on my LG range myself?
Some causes of F3 are DIY-friendly, such as reseating a loose connector at CN03 or cleaning moisture from the keypad area. However, if the Touch PCB or main PCB needs replacement, the repair requires disassembling the control panel and working near high-voltage components, which is best handled by a qualified technician. Always disconnect power to the range before inspecting any internal wiring or connectors.
Is it safe to use my LG range while the F3 error is displayed?
It is not recommended to operate the range while F3 is active. The error indicates that the touch control system is malfunctioning, which means keypad inputs may not be processed correctly or reliably. This could result in unintended behavior from the control system, so the range should be powered off and inspected before further use.
Will resetting my LG range clear the F3 error?
Disconnecting the range from power for a few minutes and then restoring power may temporarily clear the F3 code if the fault was caused by a transient signal issue. However, if the underlying cause is a hardware problem such as a damaged connector, failed Touch PCB, or wiring fault, the error will return. A reset is a useful first step but is not a substitute for proper diagnosis and repair.
How much does it cost to repair an F3 error on an LG range?
Repair costs vary depending on the root cause. If only a connector needs reseating or a wiring harness needs replacement, costs are generally in the range of $50 to $150 for parts and labor. If the Touch PCB requires replacement, expect costs in the $100 to $250 range. Main PCB replacement is the most expensive scenario, typically running $200 to $450 or more depending on labor rates and part availability.

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