LG Air Conditioner Error Code 75

Error code 75 on an LG air conditioner indicates a Fan CT sensor error. The microcomputer has detected that the fan motor phase current sensing offset voltage is not at the required 2.5V reference. This means the control board cannot accurately monitor fan motor current, so it shuts down to prevent damage. The fault is typically caused by a failed fan PCB or a problem with the 15V supply to that board.

A power reset may temporarily clear the code, but if the underlying hardware fault is still present, the error will return once the unit attempts to operate the fan again. The 2.5V offset issue is a hardware-level fault that requires diagnosis and likely component replacement, not just a reset.

Repair costs depend on the root cause. If only a wiring connector needs cleaning or reseating, costs are minimal. A replacement fan PCB assembly typically ranges from around 80 to 250 dollars for the part, plus labor costs that generally fall between 75 and 200 dollars depending on your location and the technician. If the main control board is also involved, total repair costs can be higher.

A knowledgeable DIYer can start by checking for loose or corroded wiring connectors between the main board and the fan PCB. Measuring the 15V input voltage at the fan PCB requires a multimeter and basic electrical knowledge. However, if the fan PCB assembly needs replacement, working inside the unit involves high-voltage components and is best handled by a qualified technician.

No, it is not advisable to continue operating the unit with this error active. The fault indicates the control system cannot properly monitor fan motor current, which means overcurrent conditions or motor damage could go undetected. Continued operation could lead to further component failure or a safety hazard.