LG Air Conditioner Error Code CA

The CA code on an LG air conditioner indicates the discharge pipe thermistor (D-Pipe TH) on the outdoor unit has been detected as either shorted or open. This sensor monitors the temperature of the refrigerant line leaving the compressor and should read approximately 200 kilohms at 25 degrees Celsius. When the resistance falls outside acceptable limits, the system shuts down and displays CA to prevent damage. The fault originates at the outdoor unit and requires inspection of the thermistor, its wiring, and the CN-D_PIPE connector on the outdoor PCB.

No, the unit should not be operated while the CA error is active. The discharge pipe thermistor is a protective sensor that prevents the compressor from running under unsafe temperature conditions. Without accurate readings from this sensor, the system cannot protect itself from overheating, which could cause compressor damage or a refrigerant-related failure. The system will typically refuse to operate until the fault is resolved.

If only the discharge pipe thermistor needs replacement, parts and labor typically range from around 80 to 200 dollars depending on the specific model and local labor rates. If the outdoor PCB is the root cause, repair costs can range from 250 to 600 dollars or more, as control boards are significantly more expensive. A service call for diagnosis alone generally runs between 75 and 150 dollars, which is usually applied toward the total repair cost.

A knowledgeable DIYer can start by checking whether the thermistor connector is firmly seated at the CN-D_PIPE port on the outdoor PCB, which requires only removing the outdoor unit cover. Testing the thermistor resistance with a multimeter is also straightforward if you have experience with electrical measurements. However, if the thermistor needs replacement or the outdoor PCB is faulty, working with refrigerant-side components and high-voltage outdoor circuitry is best left to a licensed technician.

A power reset may temporarily clear the CA code, but it will return if the underlying fault in the thermistor, wiring, or connector is not repaired. Resetting the unit without addressing the root cause risks repeated shutdowns and potential compressor stress. The fault should be properly diagnosed and repaired before resuming normal operation.