LG Air Conditioner Error Code 133

Error code 133 on an LG air conditioner indicates that the discharge temperature sensor on compressor 1 of the Sub2 outdoor unit has been detected as open or short in a 3-unit system. This sensor monitors refrigerant temperature leaving the compressor, and the system cannot read a valid signal from it. The control board halts the affected compressor to prevent overheating damage until the fault is resolved.

Yes, operating a compressor without a functioning discharge temperature sensor is a safety risk because the system cannot detect overheating conditions that could damage the compressor or cause refrigerant system failures. LG's control logic shuts down the affected compressor when this fault is detected, which is the correct protective response. Do not attempt to bypass or ignore this fault code.

Repair costs vary depending on the cause. If the fix is simply reseating a connector, labor costs may range from around 75 to 150 dollars for a service call. If the discharge temperature sensor needs replacement, parts and labor combined typically fall in the range of 150 to 350 dollars. If the outdoor unit control board has failed, that repair is more involved and can range from 400 to 800 dollars or more depending on parts availability and labor rates in your area.

Start by inspecting the discharge temperature sensor connector on the Sub2 outdoor unit for looseness, corrosion, or damage and reseat it firmly. If the connection is secure, use a multimeter to measure the resistance of the sensor itself to determine whether it is open or shorted. If the sensor has failed, it will need to be replaced. If the sensor reads correctly but the fault persists, check the wiring harness between the sensor and the control board for damage.

A power reset may temporarily clear the fault code, but it will return as soon as the control board attempts to read the sensor again if the underlying problem has not been fixed. Because this fault is caused by a hardware issue with the sensor or its wiring, clearing the code without repairing the root cause will not restore normal operation. The fault must be diagnosed and corrected for the unit to run reliably.