Error code reference

LG Dishwasher Error Code F-1

Door circuit

LG codesLG dishwasher codes

Door circuit - board component failure; dryer is inoperative.

First step from the service manual

Replace microprocessor board.

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

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What F-1 means on a LG dishwasher

The F-1 error on an LG dishwasher signals a door circuit board component failure detected by the main control system. Specifically, the microprocessor has identified a fault within the door circuit that renders the dryer inoperative. This is a board-level failure, meaning the control electronics governing the door circuit have malfunctioned rather than a simple mechanical or wiring issue. The first diagnostic and repair action per LG service guidance is replacement of the microprocessor board.

For homeowners, this error means your dishwasher's control board has detected a problem with the electrical circuit connected to the door. As a result, the drying function will not work. Your dishes may still wash, but they will come out wet at the end of the cycle. The dishwasher is not in a condition where normal drying operation is possible until the fault is resolved. This is not a problem you can reset away by unplugging the unit, as the underlying board component has failed and needs to be physically replaced to restore full function.

Source: manufacturer service documentation.

Common causes of F-1

  1. 01

    Failed microprocessor board

    Part replacement

    The microprocessor board itself has a component-level failure within the door circuit portion of its circuitry. This is the primary cause indicated by the F-1 code and is the first part LG service procedures direct technicians to replace.

  2. 02

    Damaged door circuit wiring harness

    Part replacement

    Wiring between the door assembly and the main board can develop breaks, shorts, or loose connectors over time, causing the board to register a door circuit failure even if the board itself is intact. Inspecting and replacing the harness may resolve the error before committing to a board replacement.

  3. 03

    Faulty door latch or door switch assembly

    Part replacement

    A defective door latch or door switch can send incorrect signals through the door circuit, triggering the F-1 fault. If the switch fails internally, the board interprets this as a circuit component failure on the door side.

  4. 04

    Corrosion or moisture intrusion at board connectors

    Wiring / connection

    Steam and moisture inside the dishwasher cavity can reach board connectors over time, causing oxidation that disrupts the door circuit signal. Cleaning or reseating connectors may be a preliminary step, but if the board traces are corroded, the board will require replacement.

See the test procedure for each cause

Frequently asked questions about F-1

What does the F-1 error code mean on an LG dishwasher?
The F-1 code on an LG dishwasher indicates a door circuit board component failure. The microprocessor has detected a fault in the door circuit, which causes the dryer to stop working. The washing portion of the cycle may still run, but drying will be inoperative until the fault is corrected.
How do I fix the F-1 error on my LG dishwasher?
LG's service procedure for F-1 starts with replacing the microprocessor board, as the fault points to a board-level failure in the door circuit. Before purchasing a board, check the door circuit wiring harness and connectors for damage, corrosion, or loose connections, since a wiring issue can produce the same error. If the wiring checks out, the board replacement is the correct repair. A technician with appliance electronics experience can complete this job, though it is a more involved repair than a simple component swap.
Can I still use my LG dishwasher with the F-1 error active?
The dishwasher may still complete a wash cycle with F-1 active, but the drying function will not operate, so dishes will come out wet. Continued use is generally not harmful to the machine in the short term, but running it repeatedly with a board fault present is not advisable. Arrange for repair before relying on the unit for regular use.
How much does it cost to fix an F-1 error on an LG dishwasher?
Replacement microprocessor boards for LG dishwashers typically range from $80 to $200 for the part, depending on the model. If you hire a technician, expect labor costs of $100 to $200 on top of the part, bringing the total repair to roughly $180 to $400. DIY replacement is feasible if you are comfortable working with appliance electronics and disconnecting wire harnesses, and it significantly reduces the cost.
Will resetting my LG dishwasher clear the F-1 error?
A power reset by unplugging the dishwasher for several minutes will not clear the F-1 error permanently because the fault is tied to a failed board component, not a temporary software glitch. The error will return once the unit powers back on and the microprocessor runs its self-check. A physical repair of the door circuit or board replacement is required to resolve it.

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