LG Air Conditioner Error Code 148

Error code 148 indicates that the voltage detection circuit on the sub1 outdoor unit is out of order. This means the outdoor unit's control system cannot confirm that the incoming electrical supply is within the required operating range. The system will typically shut down the outdoor unit as a protective measure until the fault is resolved.

No. Error 148 indicates the system cannot confirm the power supply is operating within safe parameters. Running the unit under abnormal voltage conditions risks damaging the compressor, control boards, and other expensive components. Leave the unit off until the cause of the fault has been identified and corrected.

Repair costs vary depending on the cause. If the fix is simply replacing a blown outdoor line fuse, parts and labor costs are relatively low, typically in the range of $75 to $200. If the outdoor unit control board has failed, board replacement parts alone can range from $150 to $500 or more, with additional labor costs on top. A diagnostic service call to identify the exact cause is the necessary first step.

Some basic checks, like verifying the outdoor disconnect is fully closed and inspecting for a tripped breaker, are safe for a homeowner to perform. However, testing fuses, measuring supply voltage under load, and diagnosing control board faults requires working inside live electrical panels and outdoor unit enclosures, which carries serious shock risk and should be handled by a qualified technician.

A power reset may temporarily clear the code if the fault was caused by a momentary voltage fluctuation, but the error will return if the underlying problem persists. If the code returns after a reset, the root cause, whether a supply voltage issue, a blown fuse, or a board fault, must be diagnosed and repaired for the error to stay cleared.