LG Refrigerator Error Er MS — What It Means & How to Fix It

What Does This Error Mean?

Er MS on an LG refrigerator indicates a moisture sensor fault. Some LG models include a humidity or moisture sensor that monitors conditions inside specific compartments — such as a crisper drawer or fresh food zone. When this sensor fails or sends readings outside the expected range, Er MS appears. The main cooling system is not affected. Food safety is not immediately at risk, but the humidity-controlled compartment may not function optimally.

Affected Models

LG LRMVS3006S
LRFXS2503S
LG models with Smart ThinQ fresh food management
LG French door models with humidity-controlled crispers

Common Causes

The moisture sensor has failed due to age or exposure to prolonged humidity
Condensation has accumulated on the sensor, causing it to short circuit or read incorrectly
The wiring harness to the sensor has been damaged when the crisper drawer was removed
The sensor connector has corroded from long-term exposure to the humid crisper environment
A firmware or software glitch on the main control board is misreading the sensor output

How to Fix It

Unplug the refrigerator for 60 seconds and plug it back in. Check if Er MS returns. A power cycle can resolve software-generated false alarms.

If Er MS disappears after a reset and the refrigerator has Smart ThinQ connectivity, check whether a firmware update is available via the LG ThinQ app. Firmware updates occasionally fix sensor-related errors.
Remove the crisper drawers and look at the rear wall of the crisper compartment. You may see the moisture sensor — a small component with a wiring connector. Check that the connector is fully seated.

The sensor location varies by model. On some models it is embedded in the drawer itself rather than the compartment wall. Consult your owner's manual or the LG support page for your specific model.
Dry the crisper area thoroughly with a clean cloth. Excessive moisture on or around the sensor can cause false readings. After drying, plug the refrigerator back in and check if the error clears.

This is especially relevant if the error appeared after placing very wet produce (like freshly washed vegetables) directly in the crisper without drying them first.
Check the LG ThinQ app for your refrigerator (if your model supports it). Er MS may appear as a notification with additional information about the fault. You may also find a self-diagnosis option in the app that can help identify the exact cause.

LG Smart ThinQ connected models can sometimes perform remote diagnostics that narrow down whether the fault is the sensor or the control board.
If Er MS persists after all of the above steps, the moisture sensor has likely failed and needs to be replaced by an LG-authorized technician. The repair is straightforward and typically completed in one service visit.

Bring your model and serial number when calling for service. This helps the technician bring the correct replacement sensor.

When to Call a Professional

Er MS is a low-urgency repair. Moisture sensor replacement typically costs $50–$150 including labor. If a control board firmware update is available, it may resolve a false Er MS at no parts cost. Contact LG at 1-800-243-0000 to check warranty status and whether a software fix is available for your model.

Frequently Asked Questions

What does the moisture sensor do in an LG refrigerator?

The moisture sensor measures humidity levels inside the crisper or fresh food compartment. This data allows the refrigerator to adjust its humidity settings to keep produce fresh longer. Some LG models use this data to display freshness recommendations on their displays or in the ThinQ app. When the sensor fails, the humidity optimization feature stops working.

Is my food safe with Er MS showing?

Yes — the main refrigerator temperature is not affected by Er MS. Food safety requires temperatures below 40°F (4°C), which the refrigerator maintains independently of the moisture sensor. The only concern is that your crisper drawer may not maintain optimal humidity for produce, potentially shortening freshness slightly.

Does Er MS affect my LG refrigerator's energy efficiency?

Minimally. The moisture sensor is a passive monitoring component, not part of the active cooling cycle. A faulty moisture sensor will not cause the compressor to run more often or consume significantly more energy. Energy use remains essentially normal.