LG Air Conditioner Error Code 137

Error code 137 indicates that the liquid pipe temperature sensor on the sub2 outdoor unit is reading as either open or short circuit. This sensor monitors refrigerant temperature at the condenser liquid line and is critical for safe system operation. The fault causes the control system to flag an error because it cannot obtain a valid temperature reading. LG directs technicians to follow the CH113 diagnostic procedure to identify whether the sensor, wiring, or control board is responsible.

Running the system with error code 137 active is not recommended. Without a valid reading from the liquid pipe temperature sensor, the control system cannot properly regulate refrigerant flow or protect the compressor from overheating or overcooling conditions. Continued operation could result in compressor damage or reduced system lifespan. It is best to stop using the unit until the sensor fault is resolved.

Repair costs vary depending on what component has failed. A replacement liquid pipe thermistor sensor is generally an inexpensive part, with costs typically ranging from $15 to $60 for the component alone. If a wiring harness or connector repair is needed, labor costs will add to the total, usually bringing the repair into the $100 to $250 range depending on local rates. If the outdoor unit control board requires replacement, costs can rise to $300 to $600 or more including labor.

Some basic checks, such as inspecting the sensor connector for looseness or visible wiring damage, can be performed without specialized tools. However, properly diagnosing this fault requires a multimeter to measure thermistor resistance and compare it against specification, along with access to the outdoor unit internals. Replacing a thermistor or wiring harness is within reach for experienced DIYers, but working inside the outdoor unit involves electrical hazards, so caution is essential. If you are not comfortable with electrical diagnosis, a qualified HVAC technician should handle this repair.

A reset may temporarily clear the error code from the display, but the fault will return as soon as the control board attempts to read the defective sensor again. Error code 137 reflects an actual hardware problem with the sensor circuit, not a software glitch. The underlying cause, whether a failed thermistor, damaged wiring, or faulty connector, must be repaired before the error will clear permanently.