LG Heat Pump Error Code P508

P508 indicates that the compressor has been shut down by the high pressure sensor protection control 2 function. The system detected that refrigerant pressure on the high side of the circuit reached an unsafe level and stopped the compressor to prevent damage. This is a protective fault that requires diagnosis of the underlying pressure issue before the unit can safely resume normal operation.

A power reset may temporarily clear the P508 code and allow the compressor to restart, but if the underlying cause has not been resolved, the fault will return, often within minutes of the compressor starting. Repeated high pressure shutdowns without correction increase the risk of compressor damage over time. A reset should only be used as a temporary step while arranging for a proper diagnostic.

Repair costs vary widely depending on the root cause. A coil cleaning service typically runs in the range of $100 to $250. Fan motor replacement can cost between $200 and $500 including labor. Refrigerant-related repairs such as recovering an overcharge or evacuating and recharging the system generally range from $150 to $400 or more depending on refrigerant type and quantity. A failed high pressure sensor replacement typically falls in the $150 to $350 range including parts and labor.

Some causes of P508, such as cleaning a blocked outdoor coil or clearing debris from around the unit, can be handled by a homeowner. However, issues involving refrigerant pressure, refrigerant charge, or sensor replacement require a licensed HVAC technician with proper tools and certifications. Attempting to access the refrigerant circuit without proper equipment is unsafe and illegal in most jurisdictions.

No. When P508 is active, the system has already shut down the compressor as a safety measure. Continuing to force the system to operate without addressing the cause of the high pressure condition puts the compressor at risk of serious mechanical failure. Leave the unit off and have a technician inspect it before resuming operation.