What dH means (lg dh error)
An lg dh error (Er dH) on an LG refrigerator indicates a defrost fault — the defrost cycle ran longer than about an hour without reaching its target, which usually means frost is not being cleared from the evaporator. The control raises dH so a frost buildup that chokes airflow can be addressed.
Symptoms to look for
The signs below help confirm you are dealing with this condition rather than a different fault on your LG Refrigerator. You may see one of them or several together, and they can build up gradually or appear suddenly after a power event, a long door opening, or recent service.
- The display shows “dH” or “Er dH”
- Frost builds up behind the rear interior panel
- Cooling weakens over days
- Reduced airflow from the vents
Common causes
Several different faults can produce these symptoms. Working through the most likely causes in order helps separate a quick, owner-level check from a problem that needs trained service and the correct LG parts.
- Failed defrost heater — frost is never melted
- Defrost sensor/thermostat fault — the cycle never ends correctly
- Evaporator frosted solid — heavy ice blocks airflow
- Control/timer fault — defrost logic on the board
Troubleshooting steps you can try
Work through these checks in order before calling for service. Stop wherever you are unsure, or where high-voltage parts, gas, the sealed refrigeration system, or a heat-pump compressor are involved, and hand the rest to a qualified technician.
- Note when dH appeared and watch whether cooling weakens.
- If heavy frost is visible, power off and let it thaw, protecting food.
- Restore power and watch whether airflow and cooling recover.
- Because dH is a defrost-system fault, arrange service if it recurs.
Parts a technician may replace
Depending on what the diagnosis shows, a technician may inspect, test, or replace the defrost heater, defrost sensor/thermostat, evaporator, and control board. The correct part for your LG Refrigerator is matched from the model and serial number, and genuine LG components are fitted rather than generic substitutes so that performance, safety, and the appliance’s long working life are all protected. Confirming the failed part before ordering avoids replacing more than the fault actually requires.
When to call a technician
dH needs a technician to test the defrost heater, sensor, and thermostat and replace the failed part. When the fix calls for trained service, book a visit through our scheduling page and an experienced, qualified technician will diagnose and repair it. For manufacturer documentation and model lookup, see the manufacturer at lg.com/us.
Prevention and care
Regular care keeps this condition from returning on your LG Refrigerator. Keep filters, vents, and the condenser or exhaust path clean, avoid overloading or blocking airflow, check that doors and seals close cleanly, and follow the LG maintenance guidance for your model. Because this unit relies on electronic control, protect it with a stable, correctly rated power supply and have any built-in or laundry installation done to LG specification so the control never sees an out-of-range condition. If a code appears, note exactly what was shown before you reset the appliance — that record helps the technician reach an accurate diagnosis and avoid replacing parts unnecessarily. Where stored food, a sealed refrigerant system, gas, or a safety lockout is involved, treat the condition as a reason to act quickly rather than wait.
Related help and LG resources
Browse other LG Refrigerator diagnostics, read about professional LG Refrigerator repair, look up your unit in the LG models reference, or the related dS defrost sensor fault, or schedule a service visit. For LG manufacturer documentation and model lookup, visit the manufacturer at lg.com/us.
