LG Dishwasher F31 Error Code: Heated Dry Fan Causes and Fixes

Wet dishes are frustrating, but a fan warning gives service a more specific starting point. The LG dishwasher F31 error code concerns the Heat Dry fan on models with Dynamic Heat Dry. It does not identify a failed water valve or prove the board needs replacing.

Which circuit details apply to your machine? Recording the full display and model helps avoid readings borrowed from a different design.

The explanations below cover LG’s code meaning, owner checks through normal controls, and the tests a technician needs. They also separate other drying warnings from unexplained display numbers so the repair stays focused on the correct system.

Quick Facts

Use these details to plan the work:

• Difficulty: Basic recording; moderate or advanced internal diagnosis
• Time: A few minutes to record symptoms; service time varies
• Tools: Model tag and camera for owner checks; model-specific service tools for repair
• Part cost: Obtain a quote after the failed component is confirmed
• Skill level: Trained service for internal fan and control tests

What Does the F31 Error Code Mean on an LG Dishwasher?

LG defines F31 as a Heat Dry fan motor that does not operate. Its guidance applies to models equipped with Dynamic Heat Dry.

Keep these details in mind.

• Confirm that your model has the named drying system.
• Record the entire code, including the letter F.
• Note which part of the cycle was running.
• Check whether the warning returns after normal operation resumes.

Wet dishes can have several causes, so the visible result alone is not the diagnosis. The code gives service a clearer starting point than a general drying complaint.

What Causes an F31 Error on an LG Dishwasher?

LG lists the fan motor or another related component as possible causes. The warning does not distinguish the motor from its electrical path without further tests.

These findings guide diagnosis rather than rank causes.

A finding is useful only when it matches the machine’s design. Not every motor uses the same plug, feedback arrangement, or supply voltage. A wire color is not a substitute for a wiring diagram.

How Do I Reset an LG Dishwasher Showing F31?

Use the owner’s manual for the exact model’s cancellation or power-reset steps. LG’s F31 guidance calls for service rather than giving one reset duration that repairs every model.

Start with these owner checks.

1. Photograph the full warning.
2. Note whether the machine stops or completes the wash.
3. Cancel the cycle through the normal controls if the manual permits it.
4. Follow the documented reset procedure if one is provided.
5. Arrange service if F31 remains or returns.

Did the display clear while the drying fault remained? A cleared screen does not prove that the fan works. Avoid repeated resets that erase useful details before the technician sees them.

Does the Water Inlet Valve Cause F31?

F31 concerns the Heat Dry fan. LG uses IE for a water-inlet problem, so a fill complaint and F31 need to be recorded separately.

Keep the repair focused.

• Do not order a valve from F31 alone.
• Record any additional code exactly.
• Tell service if filling or draining also fails.
• Use the correct circuit diagram for internal checks.

A nearby valve or connector does not establish a shared electrical fault. The position of parts behind an access panel can differ by model. That is why a general instruction to reseat every heater or sensor plug can lead away from the actual problem.

How to Fix an LG F31 Error Step by Step

Owner checks prepare the diagnosis. Internal work belongs with trained service using the model’s instructions.

Phase 1: Identify the Model and Drying Fault

1. Record the complete model and serial numbers.
2. Photograph F31 and note when it appears.
3. Check the owner’s manual for the drying feature and controls.
4. Arrange a detailed service inspection if the fault persists.

Phase 2: Inspect the Disconnected Fan Circuit

1. Have service disconnect power before opening panels.
2. Locate the fan using the model diagram.
3. Inspect its mounting, connections, and accessible fan path.
4. Correct confirmed loose or damaged connections.

Phase 3: Test the Motor, Harness, and Control

1. Use the exact service sheet for terminals and expected readings.
2. Check isolated wiring and components with power off as specified.
3. Leave any required powered measurement to a trained technician.
4. Identify the failed component before selecting parts.

Phase 4: Reassemble and Verify Drying Operation

1. Fit the correct replacement if a fault is confirmed.
2. Refit all panels before normal operation.
3. Run the prescribed verification cycle.
4. Check fan operation and that F31 does not return.

There is no safe universal blue-wire voltage chart for every dishwasher displaying F31. Resistance tests also require power to be disconnected and the circuit isolated as directed. Do not improvise live measurements behind an open panel.

Should You Replace the Fan Motor, Harness, or Control Board?

The test results determine the part. An LG dishwasher F31 error code alone does not prove any one component has failed.

Compare these choices after diagnosis.

• Connection repair: Appropriate for a confirmed loose or damaged terminal.
• Fan motor: Appropriate when it fails the specified operation test.
• Harness: Appropriate when a wire or connector fault is isolated.
• Control: Consider after the motor and wiring pass their checks.

Request separate parts and labor quotes. Check warranty coverage before paying. Access, diagnosis, and related damage can affect the total, so a generic motor price may not reflect the final bill.

What Do LG Dishwasher Error Codes 18 and 36 Mean?

A bare 18 or 36 does not give enough information here to identify a component. Record the complete display and model, then check that appliance’s manual instead of assuming a universal fault meaning.

These published LG codes show why the full characters matter.

FAQ

When Should I Call a Technician for an LG Dishwasher F31 Error?

Call when the warning persists or returns. LG recommends detailed inspection because the fan or related parts may be at fault.

Can I Run the Dishwasher Without Heated Dry While Waiting?

Ask for advice for the exact model and symptoms. Turning off an option does not establish that an unresolved electrical fault is safe to ignore.

Drying With the Fan Working Again

An LG dishwasher F31 error code needs a fan-system diagnosis on the matching Dynamic Heat Dry model. Confirm the failure before buying parts.

Have the faulty component identified, then match the full model to the replacement dishwasher part needed for the repair.