LG Heat Pump Error Code tu

The TU code on an LG heat pump indicates that the outdoor temperature has dropped below -5 degrees Celsius, which prevents the unit from running in cooling mode. This is a built-in protection feature designed to safeguard the compressor and refrigerant system. It is not a malfunction or component failure. The system will resume cooling automatically when outdoor temperatures rise above the threshold.

Yes, the TU code means the system is actively protecting itself by refusing to run cooling mode in conditions that could cause damage. The heat pump is behaving correctly. You should not attempt to bypass or override this protection feature, as running the compressor in cooling mode below -5°C can cause serious refrigerant circuit and compressor damage.

If TU is appearing correctly due to cold outdoor temperatures, there is no repair cost at all. If a faulty outdoor temperature sensor is causing a false TU lockout, sensor replacement parts typically range from $20 to $80, with professional labor adding $75 to $200 depending on your market. A control board replacement, if needed in rare cases, can range from $150 to $400 or more for parts alone.

In most cases, no fix is needed because TU is a protective interlock that clears itself when outdoor temperatures rise above -5°C. If the code appears during warm weather, check whether the outdoor ambient temperature sensor is functioning correctly and inspect its wiring for damage or corrosion. A faulty sensor may require replacement to restore accurate temperature monitoring.

Performing a reset will not permanently clear the TU code if the outdoor temperature remains below -5°C. The code will reappear because the underlying condition, cold outdoor air temperature, still exists. The lockout will clear on its own once the outdoor temperature rises above the minimum threshold without any manual reset required.