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Error code reference

LG Range Error Code F20

Lower oven door lock failure

LG codesLG range codes

Lower oven door lock failure — door lock switch does not operate properly after lock motor rotates twice.

First step from the service manual

Check operation of door lock motor by pressing Lower Clear/Off for 3 seconds and trying to open door.

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

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What F20 means on a LG range

The F20 error code on an LG range indicates a lower oven door lock failure. Specifically, the door lock switch does not register proper operation after the door lock motor has completed two full rotation cycles. This failure is detected during the self-clean cycle, when the control board commands the lock motor to engage and then monitors the lock switch for confirmation that the door has been secured. If the switch signal never confirms a locked state after two motor attempts, the board throws F20 and halts the process.

The door lock system consists of three main components working together: the lock motor, the lock switch, and the wiring harness connecting them to the control board. The motor physically drives a latch mechanism across the door frame, and the switch acts as a position sensor that tells the board when the latch has reached the fully locked position. A failure in any one of these components can produce F20. The motor may be running but failing to move the latch, the latch may be moving but the switch is not actuating, or wiring faults between the components and the board may be preventing signal transmission.

Common root causes include a seized or burned-out lock motor, a faulty or misaligned door lock switch, debris or grease buildup obstructing the latch mechanism, and wiring harness damage from repeated heat exposure in the rear of the oven cavity. The first diagnostic step is to press and hold the Lower Clear/Off button for 3 seconds and then attempt to open the door, which helps determine whether the motor is responding to commands and whether the door is physically locked or just electronically flagged as such.

Source: manufacturer service documentation.

Common causes of F20

  1. 01

    Faulty door lock switch

    Part replacement

    The lock switch is the sensor that confirms the latch is in the locked position. If the switch is worn, burned, or misaligned, it will not send the confirmation signal to the board even when the latch physically engages.

  2. 02

    Failed or seized door lock motor

    Part replacement

    The lock motor drives the latch mechanism into position. If the motor has burned out, seized from heat damage, or lost torque, it will not complete the locking stroke even though the board commands it to run.

  3. 03

    Latch mechanism obstruction

    Wiring / connection

    Grease buildup, food debris, or physical damage around the door latch cavity can block the latch from traveling fully into the locked position, preventing the switch from actuating.

  4. 04

    Wiring harness damage

    Part replacement

    The wiring between the lock motor, lock switch, and control board runs near the oven cavity and is exposed to high heat over time. Burned, frayed, or disconnected wires can interrupt both the motor drive signal and the switch feedback signal.

  5. 05

    Control board fault

    Part replacement

    If the board is not sending proper voltage to the lock motor or not reading the switch signal correctly, F20 can appear even when the mechanical components are in good condition. This is the least common cause and should be diagnosed only after other components are ruled out.

See the test procedure for each cause

Frequently asked questions about F20

What does F20 mean on a LG range?
F20 on an LG range means the lower oven door lock has failed to confirm a locked position after the lock motor ran two cycles. This is typically triggered during a self-clean cycle when the control board commands the door to lock but receives no confirmation from the door lock switch. The issue can involve the lock motor, the lock switch, the latch mechanism, or the wiring connecting them.
Can I reset the F20 error code to clear it?
You can attempt a reset by pressing the Lower Clear/Off button for 3 seconds, which is also the first recommended diagnostic step. This may release the door if it is physically locked and allow you to inspect the latch area. However, simply clearing the code without addressing the underlying cause will result in F20 returning the next time a self-clean cycle is attempted.
Is it safe to use my LG range with an F20 error?
Normal baking and broiling functions may still be available while F20 is active, but you should not attempt another self-clean cycle until the fault is repaired. If the door is stuck in a locked position, do not force it open, as this can damage the latch assembly and door hinge components. Address the fault before using the self-clean feature again.
How do I fix F20 on my LG range?
Start by pressing and holding the Lower Clear/Off button for 3 seconds to test the lock motor response and release the door if needed. Then inspect the latch mechanism for obstructions, grease buildup, or physical damage. If the latch area is clear, the next steps are testing the door lock switch for proper operation and checking the wiring harness for heat damage or disconnected connectors. If the motor or switch is defective, those components will need to be replaced.
How much does it cost to repair an F20 error on an LG range?
Repair costs vary depending on which component has failed. A door lock switch or lock motor typically costs between $30 and $90 for the part alone. If you hire a technician, expect to pay between $150 and $300 or more including labor, depending on your location and the extent of the diagnosis required. Wiring harness repairs or control board replacement can push costs higher.

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