LG · Refrigerator Moderate

Er rt — Room (ambient) temperature sensor fault

The external ambient temperature sensor is open, shorted, or disconnected. The board uses this for anti-sweat / condensation heater logic and may default to a fixed value.

Keep using it?
Yes, with caution
DIY difficulty
Moderate
Verified against
lg.com ↗

How to fix it

  1. Unplug for 5 minutes to attempt soft reset.
  2. If error returns, remove the rear access panel to locate the ambient sensor (usually mounted near the machine compartment).
  3. Reseat its connector.
  4. Ohm the sensor at room temp against LG spec.
  5. Replace sensor if out of spec.
  6. If still active, replace the main control board.

Why it happens

Typical signs: Er rt on display · Anti-sweat heater always on (cabinet exterior warm) · Condensation issues around door frame · Cooling continues normally

  • Disconnected ambient sensor Plug unseated, especially after rear panel service.
  • Failed thermistor Sensor element failed open or short.
  • Main board input failure Rare ADC fault.

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.

  • Ambient/room temp sensor 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.