LG Air Conditioner Error Code E374

E374 indicates a heat sink temperature sensor error on the second inverter PBA (PBA2), which is the control board that regulates compressor speed. The sensor monitors the temperature of the inverter's heat sink to protect the power transistors from overheating. When the sensor reads an out-of-range or implausible value, the unit shuts down and displays E374. The fault points to either a failed sensor circuit on the board, a wiring issue, or an actual overheating condition.

No. The E374 error causes the unit to shut down automatically as a protective measure, and you should not attempt to force it to restart repeatedly. The heat sink sensor monitors inverter temperatures to prevent damage to the compressor drive circuit, and operating without proper thermal protection risks permanent damage to the inverter board or compressor. Leave the unit off until the fault is diagnosed and repaired.

Repair costs vary depending on whether the fix involves a wiring correction or a full inverter PBA2 board replacement. Wiring repairs may fall in the range of $75 to $200 in labor. Inverter board replacement, including parts and labor, typically ranges from $250 to $600 or more depending on the specific model and regional labor rates. Getting a diagnostic visit from a certified LG technician will give you an accurate estimate for your particular unit.

Some preliminary checks, like inspecting the wiring harness connector for looseness or corrosion and ensuring airflow to the inverter compartment is unobstructed, can be done by a knowledgeable DIYer. However, if the inverter PBA2 board itself has failed, replacing it involves working with high-voltage inverter components and requires proper technical knowledge and safety precautions. Most homeowners should have a qualified HVAC technician handle the board replacement.

A power reset may temporarily clear the error display, but if the underlying cause is a failed sensor circuit on the inverter PBA2 or a persistent wiring fault, the code will return once the unit attempts to operate. A reset is only likely to provide a lasting fix if the fault was caused by a momentary electrical anomaly. The correct approach is to diagnose and repair the root cause before relying on the unit for normal operation.