LG Refrigerator Error Code Er rS

Er rS means the main control board has detected a fault with the refrigerator compartment temperature sensor. The board found either a short circuit or a disconnection in the sensor circuit. This prevents accurate temperature monitoring in the fresh food section and requires diagnosis of the sensor and its wiring harness.

The refrigerator may continue running with Er rS active, but the control board cannot accurately regulate the temperature in the fresh food compartment without a working sensor. This means the fridge section could run too warm or too cold. Do not store perishable food or medications in the refrigerator section until the sensor fault is resolved, as temperatures may be unpredictable.

Disconnect the refrigerator sensor connector from the wiring harness and measure resistance across the sensor terminals with a multimeter set to ohms. At room temperature, a working LG refrigerator thermistor should read around 5,000 ohms. A reading of zero (short) or infinite resistance (open circuit) confirms the sensor has failed and needs replacement. If the sensor reads correctly, inspect the wiring harness between the sensor and control board for damage before replacing any parts.

Start by unplugging the refrigerator and locating the refrigerator sensor wiring connector, typically found at the back wall of the fresh food compartment or near the control board housing. Check that the connector is fully seated and that no wires are visibly pinched or broken. If the wiring looks intact, test the thermistor with a multimeter for correct resistance at room temperature (most LG fridge thermistors read approximately 5,000 ohms at 77 degrees F). Replace the sensor if it reads open or shorted.

If the fix is a reconnected wiring harness, the cost is nothing beyond your time. An LG refrigerator thermistor typically costs between 10 and 40 dollars as a replacement part. If professional service is needed, expect a labor charge of 80 to 150 dollars on top of parts. A control board replacement, the least likely fix, can cost 150 to 300 dollars for the part alone, making professional diagnosis worthwhile before replacing it.