LG · Refrigerator Serious

Er rS — Refrigerator (fresh-food) sensor open/disconnected

The fresh-food compartment thermistor is reading open or is unplugged from the main board, so the unit can't regulate fridge temperature.

Keep using it?
Limited use only
DIY difficulty
Moderate
Verified against
lg.com ↗

How to fix it

  1. Unplug the refrigerator.
  2. Remove the fresh-food rear panel or sensor cover and locate the thermistor.
  3. Inspect the harness connector and reseat it firmly.
  4. Ohm the thermistor at a known room temperature against LG spec sheet.
  5. If out of range or open, replace the sensor (kit usually inexpensive).
  6. Restore power and confirm Er rS clears.

Why it happens

Typical signs: Er rS on display · Fresh-food side too cold or too warm · Compressor may run constantly or short-cycle

  • Disconnected sensor plug Vibration or recent service left the connector unseated.
  • Open thermistor NTC sensor failed internally.
  • Damaged harness Wire chafed at a hinge or shelf bracket.
  • Main board input failure Rare — sensor channel on PCB dead.

Parts you may need

If diagnosis points to a failed part, these are the common replacements. As an Amazon Associate we earn from qualifying purchases.

  • Fresh-food thermistor Common replacement
    Amazon →

More LG refrigerator codes

22 22 — Compressor relay / inverter control fault 33 33 — Compressor / defrost test fault 67 67 — Door open / not fully closed 88 88 — Power-on display test (not a fault) Er CF Er CF — Condenser fan motor feedback fault Er CO Er CO — Communication error (main board ↔ display)

All LG codes → All refrigerator codes →

Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician. Verified against manufacturer documentation: lg.com.