Er dH Serious Moderate DIY

LG Refrigerator Er dH — Defrost cycle exceeded time limit

LG Refrigerator · Error code Er dH

What Er dH Means

During a defrost cycle the evaporator never reached the target temperature within ~1 hour. The main board logs Er dH, meaning the heater, fuse, sensor, or relay in the defrost circuit is at fault.

Symptoms

  • Er dH (or F dH / r dH) on display
  • Freezer thick with frost on back panel
  • Both sides eventually warm
  • Fan noise reduced or stopped
  • Code returns shortly after a reset

Common Causes

1
Open defrost heater element

Glass/sheath heater burns out — the most common single cause.

2
Blown thermal fuse / bi-metal

Safety fuse opens after an overheat event and stays open.

3
Defrost sensor (thermistor) failure

Open or out-of-spec sensor — board never sees temp climb.

4
Main board relay failed

Defrost relay on the PCB won't energize the heater.

5
Wiring/harness break

Broken wire to the heater or sensor in the freezer rear panel.

How to Fix It

  1. Unplug the unit for 2 minutes, then restore power — clears one-time faults.
  2. If Er dH returns within a day, remove the freezer rear panel.
  3. With a meter, ohm the defrost heater (typical 20–60 Ω); infinity = open, replace it.
  4. Ohm the thermal fuse / bi-metal cold; should read continuity. If open, replace as a kit with the heater.
  5. Check the defrost thermistor against the LG spec chart; replace if out of range.
  6. If all defrost parts test good, replace the main control board (relay failure).

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.

Common replacement Defrost heater + thermal fuse kit View on Amazon→ Common replacement Defrost thermistor View on Amazon→ Common replacement Main control board View on 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 Fault Er CO Er CO — Compressor / Communication Fault

All LG codes → All refrigerator codes →

Verified against manufacturer documentation: lg.com

Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician.