LG Heat Pump Error Code E151

E151 indicates an indoor unit Electronic Expansion Valve (EEV) open failure. The EEV controls refrigerant flow into the indoor coil, and this error means the system detected that the valve is not opening as commanded. The heat pump will typically suspend operation until the fault is resolved to prevent refrigerant circuit damage.

You should not attempt to run the heat pump while E151 is active. The error indicates the expansion valve is not controlling refrigerant flow correctly, which can cause inadequate cooling or heating and may damage the compressor or other refrigerant circuit components if operation continues.

Repair costs vary depending on the cause. If the fix is simply reseating a wire or the EEV coil, there may be no parts cost, only a diagnostic service call fee, which typically ranges from $75 to $150. If the EEV coil or valve body requires replacement, total parts and labor costs generally range from $200 to $600 depending on the specific unit and local labor rates.

Some causes of E151 are accessible to a knowledgeable DIYer. You can inspect and reseat the EEV wire harness and verify the EEV coil is properly inserted onto the valve body, then press the reset key (K3) to clear the fault. However, if the coil or valve body itself is defective, those repairs involve the refrigerant system and require a licensed HVAC technician.

Pressing the reset key (K3) is the recommended first step after checking the EEV wiring and coil insertion. If the underlying issue has been corrected, the reset will clear the fault and allow normal operation to resume. If the root cause has not been addressed, the error will return after the reset.