LG Heat Pump Error Code E464

E464 indicates that the outdoor unit's Electronic Expansion Valve (EEV close 1) has failed a self-diagnosis check. The system commanded the valve to close and did not receive confirmation that it reached the correct position. This can point to a faulty EEV coil, a stuck valve body, wiring problems, or a control board issue in the outdoor unit.

Operating the system while E464 is active is not recommended. The EEV controls refrigerant flow through the system, and a valve that cannot close properly can lead to refrigerant circuit imbalance, compressor stress, or further component damage. The system may shut down automatically as a protective measure, which is normal behavior.

A power reset may temporarily clear the E464 code if the fault was caused by a transient electrical issue, but if the underlying problem with the EEV coil, valve body, or wiring persists, the error will return when the system runs its self-diagnosis again. A reset alone is not a fix and should not be relied upon if the code reappears after restarting.

Some basic checks, such as inspecting the wiring harness and connector at the EEV for obvious damage or corrosion, can be performed by a knowledgeable DIYer. However, testing EEV coil resistance, diagnosing PCB output signals, and replacing refrigerant-circuit components require specialized tools and, in many regions, proper refrigerant handling certification. A qualified HVAC technician is recommended for full diagnosis and repair.

Repair costs vary depending on the root cause. Wiring repairs may fall in the range of $75 to $200 for labor. An EEV coil replacement can cost between $100 and $300 including parts and labor. Replacing the full EEV valve body or the outdoor unit PCB can range from $250 to $700 or more depending on parts availability and labor rates in your area.