LG Air Conditioner Error Code CH15

CH15 indicates a communication error between the indoor main PCB and the fan board inside the indoor unit. The two boards use a dedicated signal line to coordinate fan motor operation, and this code appears when that communication fails or becomes unreliable. The fault will prevent normal unit operation until the underlying wiring or component issue is resolved.

A power reset may temporarily clear CH15 if the fault was caused by a momentary signal disruption or electrical noise, but the code will return if a physical problem with the wiring or a board exists. Resetting without addressing the root cause is not a lasting solution. If the code comes back after a reset, a hands-on inspection is needed.

If the fix is simply reseating a loose connector, the cost may be limited to a service call fee, typically in the range of $75 to $150. Replacing a fan board generally costs between $150 and $350 in parts and labor, while replacing the indoor PCB can range from $200 to $500 or more depending on the unit model and technician rates in your area.

A homeowner comfortable working with electronics can safely check and reseat the wire connectors between the indoor PCB and the fan board, which resolves the fault in some cases. However, if the issue involves a broken wire, failed fan board, or faulty indoor PCB, those repairs typically require a qualified technician with access to replacement parts and diagnostic tools.

The unit will generally shut itself down when CH15 is active to prevent uncontrolled fan operation, so continued use is not typically possible. Even if the unit runs partially, operating it with a known communication fault between control boards is not recommended, as it could lead to further component damage.