LG Air Conditioner Error Code E391

The E391 code indicates an error related to the DataFlash memory on the Fan2 motor control board. This memory chip stores firmware and configuration data that the fan motor relies on to operate. When the system cannot successfully read or write to this chip, it triggers the E391 fault and stops normal operation. A technician will need to inspect the Fan2 motor assembly, its control board, and the wiring connecting it to the main PCB.

It is not advisable to continue running the unit while the E391 error is active. The system has flagged a failure in the Fan2 motor control circuit, which means the fan may not be operating correctly or at all. Running the unit without proper airflow can cause the compressor or heat exchanger to overheat and lead to more serious damage. Power off the unit until the fault is diagnosed and resolved.

Repair costs depend on whether the issue is a wiring problem or a failed component. Simple wiring repairs or connector replacements may cost between $75 and $150 in labor. If the Fan2 motor control board or the entire motor assembly needs replacement, parts and labor combined could range from $200 to $600 or more depending on the unit model and local service rates. Getting a diagnostic visit from a certified LG technician will provide a more accurate estimate.

Basic checks such as inspecting wiring connectors to the Fan2 motor for looseness or visible damage can be done by a knowledgeable DIYer. However, if the DataFlash chip or the Fan2 motor control board itself has failed, component-level repair or board replacement is required and is best handled by a qualified technician. Working inside an air conditioner involves electrical hazards, so always disconnect power before inspecting internal components.

A power reset may temporarily clear the code if the error was triggered by a transient power event that corrupted the DataFlash memory during a write operation. However, if the Fan2 control board or its memory chip has physically failed, the error will return after restart. A reset is worth attempting as a first step, but do not rely on it as a fix if the code comes back.