LG Air Conditioner Error Code 149

Error code 149 indicates a short voltage or excess voltage fault on the Sub2 outdoor unit in a multi-unit LG system. The unit has detected that incoming supply voltage is either above 487V or below 270V, which is outside safe operating limits. The system shuts down automatically to protect the compressor and inverter components from electrical damage.

No. Error code 149 means the system has already detected a voltage condition that is outside safe limits, and the unit should have shut down automatically. Attempting to override or repeatedly reset the unit while the underlying voltage problem persists risks damaging the compressor, inverter board, and other electrical components. The power supply issue should be resolved before the unit is returned to service.

A power reset may temporarily clear the fault and allow the unit to restart, but if the underlying voltage problem has not been corrected, the code will return quickly. Error code 149 is a protective fault that will continue to trigger as long as the input voltage at the Sub2 outdoor unit remains outside the 270V to 487V acceptable range. The voltage supply issue must be diagnosed and corrected for the system to operate reliably.

Some basic checks, such as confirming the breaker is fully seated and visually inspecting accessible wiring connections at the disconnect, can be performed by a knowledgeable homeowner. However, measuring line voltage at the outdoor unit terminal block and diagnosing supply wiring faults requires working near live electrical components and should be handled by a licensed HVAC technician or electrician. If the issue is a utility supply problem, contacting your power provider is the appropriate next step.

Repair costs depend heavily on the root cause. If the problem is a utility supply issue, there may be no cost beyond a service call fee, which typically ranges from $75 to $150. Wiring repairs or breaker replacement can range from $150 to $500 depending on the extent of work. If the outdoor unit control board requires replacement, parts and labor combined can range from $400 to $900 or more.