LG Heat Pump Error Code t8

The t8 code indicates an error with the low pressure sensor circuit. The system detected a signal voltage below 0.4V (SHORT error) or above 4.7V (OPEN error) from the sensor while the compressor was running. This means the control board cannot reliably read suction-side refrigerant pressure, and the system has flagged a fault to prevent potential damage.

It is not recommended to continue running the heat pump while the t8 fault is active. The low pressure sensor protects the compressor by alerting the system to abnormally low suction pressure, which can result from refrigerant loss or restrictions in the circuit. Operating without reliable pressure feedback increases the risk of compressor damage, which is a costly repair.

Repair costs vary depending on the cause. If the issue is simply a loose or corroded connector, a service call to diagnose and reseat the connection may cost between $75 and $150. Replacing a faulty low pressure sensor typically adds $50 to $150 in parts. If wiring harness repairs or control board replacement are needed, the total cost can range from $200 to $600 or more depending on parts availability and labor rates in your area.

A homeowner can safely inspect the sensor wiring harness and connector for obvious damage, corrosion, or loose connections without working on the refrigerant system. However, if the sensor itself needs replacement or if refrigerant pressure is involved in confirming the diagnosis, a licensed HVAC technician should complete the repair. Working inside the unit near live electrical components also carries risk if you are not experienced with appliance repair.

A power reset may temporarily clear the fault code, but if the underlying wiring fault or sensor failure is still present, the t8 error will return once the compressor starts running again. The fault is only detected during compressor operation, so the error will reappear during the next active heating or cooling cycle. The root cause must be identified and repaired for the code to stay cleared.