LG Air Conditioner Error Code 140

Error code 140 means the high pressure switch in the sub2 outdoor unit has detected excessive refrigerant pressure and shut off the compressor to prevent damage. This is a protective fault that stops operation until the underlying cause of the pressure rise is corrected. The system will not resume normal cooling until the fault is cleared and conditions return to safe levels.

No. The compressor has already been shut down by the high pressure switch as a safety measure, and the system should not be forced to operate while this fault is active. Attempting to bypass or ignore the fault risks compressor damage, refrigerant line failure, or injury. Leave the unit off and have it inspected before restarting.

Repair costs vary widely depending on the cause. A condenser coil cleaning typically runs in the range of $75 to $200. Replacing a condenser fan motor may cost $150 to $400 including labor. High pressure switch replacement is generally $100 to $250. If the compressor was damaged due to repeated high pressure events before the fault was addressed, replacement costs can exceed $1,000 to $1,500 or more.

The first step, checking that the high pressure switch connector is securely seated at the PCB, can be done by a confident DIYer comfortable working around electrical components. However, tasks like measuring refrigerant pressures, testing the high pressure switch, or adjusting refrigerant charge require certified HVAC technicians with proper equipment and certifications. Cleaning the condenser coil is also a DIY-accessible step that sometimes resolves the fault.

A reset may temporarily clear the fault code and allow the system to restart, but if the root cause of the high pressure condition has not been fixed, the switch will trip again and the error will return. Repeated resets without diagnosis can stress the compressor and other components. A proper inspection is needed to confirm the fault is resolved before relying on the unit for cooling.