LG Air Conditioner Error Code 12

Error code 12 on an LG air conditioner signals a problem with the connecting cables between the indoor and outdoor units, or a connecting pipe issue that is causing abnormal refrigerant pressure. The system detects a failure in the communication or physical connection between the two units and shuts down to protect components. This fault requires inspection of the wiring terminals and refrigerant line routing at both units.

Start by turning off and unplugging the unit, then inspect the multi-conductor cable connecting the indoor and outdoor units at both terminal blocks. Verify each wire is connected to the correct numbered terminal, is fully seated, and shows no signs of damage or corrosion. Also check that the refrigerant connecting pipes are not kinked or pinched. After correcting any issues found, plug the unit back in to reset and restart the system.

If the fix is simply reconnecting or tightening a loose terminal, the cost may be limited to a service call fee, which typically ranges from $75 to $150. If the connecting cable is damaged and needs replacement, parts and labor together can range from $150 to $400 depending on the cable length and the complexity of the routing. Refrigerant line repairs or re-routing can add additional cost depending on the extent of the work required.

A full power reset by unplugging the power cord and re-inserting it is required to attempt a restart after error code 12 appears. Simply using the remote control or pressing a reset button on the unit is not sufficient to clear this fault. If the underlying wiring or pipe issue is not corrected, the error code will return shortly after the unit restarts.

The unit will not operate normally while error code 12 is active, which limits immediate safety risks from a running system. However, damaged wiring between units or improperly routed refrigerant lines can pose electrical and refrigerant hazards if left unaddressed. It is best to have the connecting cable and piping inspected promptly, particularly if there is any visible damage to the wiring or signs of moisture at the terminal blocks.