Samsung Air Conditioner Error Code E366

E366 indicates a voltage fault at the inverter PBA2, which is the secondary inverter control board in the unit. The system has detected either an over voltage or low voltage condition at this board and has shut down to prevent component damage. The fault can stem from the incoming power supply, internal board components, or wiring connections.

No. The unit should not be operated while displaying E366. The error indicates the inverter board is experiencing a voltage condition outside its safe operating range, and continuing to run the system could damage the inverter PBA2, the compressor, or other components. Keep the unit off until the fault has been diagnosed and resolved.

Repair costs depend on the root cause. If the issue is only a wiring connection or an external voltage problem, costs may be limited to a service call fee in the range of $75 to $150. If the inverter PBA2 board needs replacement, parts and labor combined can range from $250 to $600 or more depending on the unit model and local labor rates.

Basic checks like verifying the incoming AC supply voltage or inspecting for a tripped breaker can be done by a knowledgeable DIYer. However, diagnosing and replacing the inverter PBA2 or its associated components involves working with high-voltage DC circuits that remain energized even after shutting off the unit, so a licensed technician should handle any internal repair work.

A power reset may temporarily clear the fault display, but if the underlying cause is still present, the error will return once the unit attempts to run. A persistent or recurring E366 code requires hands-on diagnosis of the supply voltage and the inverter PBA2 board rather than repeated resets.