LG Heat Pump Error Code E337

E337 indicates a 4-way valve operation error on an LG heat pump. The 4-way reversing valve is responsible for switching the system between heating and cooling modes, and the control board has detected that it is not operating correctly. This can be caused by a failed solenoid coil, a stuck valve, a wiring issue, or a refrigerant charge problem. The system will not function normally in both modes until the fault is resolved.

Continuing to operate the heat pump with an active E337 error is not recommended. If the 4-way valve is stuck or malfunctioning, the system may run in the wrong mode, overheat components, or cause compressor damage due to abnormal operating pressures. Shutting the unit down until the fault is diagnosed and repaired helps prevent further damage.

A power reset may temporarily clear the E337 code, but it will return if the underlying fault with the 4-way valve or its electrical components has not been corrected. Resetting the unit does not fix a failed solenoid, a seized valve, or a wiring problem. If the code reappears after a reset, a thorough diagnostic inspection is required before the system can be returned to reliable operation.

Some basic checks, such as inspecting wiring connections and terminals at the solenoid coil, can be performed by a knowledgeable DIYer. However, testing refrigerant pressures, replacing the solenoid coil, and especially replacing a seized reversing valve all require specialized tools and EPA certification for refrigerant handling. For most homeowners, this repair is best handled by a licensed HVAC technician.

Repair costs vary depending on the root cause. Replacing a solenoid coil is generally a lower cost repair, typically in the range of $100 to $300 including labor. Replacing a fully seized 4-way reversing valve is significantly more involved and can cost anywhere from $400 to $900 or more depending on the unit size and labor rates in your area. A diagnostic service call is usually needed first to confirm the exact cause.