Defrost Sensor Error

What it means

This code appears on LG refrigerators with a digital display and means the main board is reading an impossible value from the defrost sensor on the evaporator behind the freezer's inner cover. Without a correct reading, the refrigerator does not know when to start and end defrost, so ice can build up and cooling weakens gradually; the same code can mean something else on other brands.

Models covered: LG refrigerators with a digital display (e.g. side-by-side, French door and top-freezer models); the code shows as Er plus two letters.

Related codes: ER DHER FFER FS

Symptoms4

• Er dS shows on the refrigerator display.
• Frost builds up on the back wall inside the freezer over time.
• Cooling weakens gradually.
• The freezer fan may be heard scraping against ice.

Possible causes4

• Loose or corroded sensor connector from moisture around the evaporator.
• Failed defrost sensor, open or shorted.
• Broken sensor wire from ice or earlier service work.
• A fault in the sensor input circuit on the main board.

How to diagnose5

1. Unplug the refrigerator for a few minutes and plug it back in; if the code returns, the fault is real.
2. Look inside the freezer; heavy frost on the back wall means defrost has been affected.
3. Keep the doors closed and watch how cold the food stays until the repair.
4. A technician unplugs the refrigerator before removing the inner cover, then measures the sensor resistance against the LG temperature-resistance table.
5. The technician checks the connector, wiring and defrost heater on the same visit, then the main board if those parts test good.

How to fix5

1. Clean and reseat the sensor connector, or repair the wire.
2. Replace the defrost sensor with the correct part for the model.
3. Repair the defrost heater if it is found to be affected too.
4. Replace the main board only after the sensor and wiring are confirmed good.
5. The technician melts the built-up ice, then the refrigerator is run to confirm cooling returns without the code.

Repair cost

In Saudi riyals; the highlighted part is the expected range for this fault.

The usual repair is a low-cost sensor plus the labor to remove the inner cover; the price rises if the defrost heater or main board must be replaced.

Prices are rough estimates including the part and the technician’s fee, and vary with brand, model and part source.
Prices last updated: September 2026

Frequently asked questions