LG Air Conditioner Error Code 25

Error code 25 on an LG air conditioner means the outdoor unit has detected an input voltage that is either above 487V or below 270V, which is outside the safe operating range. The unit shuts down automatically to protect the compressor and electrical components from damage caused by abnormal voltage. This is a supply-side electrical fault, not an internal component failure in most cases. The first step is to check the L1 and L2 wiring connections and verify that the supply voltage falls within 220V plus or minus 10% or 240V plus or minus 10%.

No, you should not attempt to override or ignore error code 25. The unit has shut down because the supply voltage is at a level that can permanently damage the inverter drive board, compressor windings, and control circuitry. Continued operation under abnormal voltage conditions can also create fire and electrical hazard risks within the wiring. Leave the unit off until the voltage supply issue has been diagnosed and corrected.

Repair costs depend entirely on the root cause of the voltage problem. If the fix is as simple as tightening a loose connection at the disconnect, the cost may only involve a service call fee, typically in the range of $75 to $150. If a circuit breaker needs replacement, costs usually range from $150 to $350 including labor. Wiring repairs or utility transformer issues can range from a few hundred dollars to over $1,000 depending on the scope of work involved.

Some causes of error code 25 are accessible to a knowledgeable DIYer, such as tightening a visibly loose terminal at the disconnect block or resetting a tripped breaker. However, measuring live voltage at the outdoor unit terminals and tracing electrical faults back through the panel requires proper safety equipment and training. If the voltage issue originates at the utility supply or involves the main panel, a licensed electrician must perform the repair. Attempting high-voltage electrical work without proper knowledge poses a serious safety risk.

A reset may temporarily clear the fault and allow the unit to restart, but if the underlying voltage problem is still present, error code 25 will return, typically within seconds or minutes of the next startup attempt. Resetting does not correct the electrical supply issue causing the fault. The error will continue to recur until the voltage is confirmed to be within the rated tolerance of 220V or 240V plus or minus 10%.