LG Heat Pump Error Code E157

E157 indicates an option setting error for the indoor unit. It means the indoor unit has detected a conflict or invalid configuration in its SW03 option switch settings, its wired remote controller address, or both. The system flags this error to prevent the unit from operating under an incorrect configuration. A technician will need to verify the switch positions and address settings to resolve it.

E157 is a configuration error rather than a safety hazard. The system uses this fault to prevent operation under misconfigured settings, which protects the unit from running incorrectly. While it is not immediately dangerous, the unit will not operate properly until the settings are corrected, so the issue should be addressed promptly to restore heating and cooling function.

If the fault is caused only by incorrect switch positions or address settings, the repair cost is primarily the service call fee, typically in the range of $75 to $150 depending on your location. If a faulty wired remote controller needs replacement, parts and labor could bring the total to $150 to $400 or more. Replacing the indoor unit control board is the most expensive scenario and could range from $300 to $600 or higher including parts and labor.

Start by locating the SW03 option switch on the indoor unit control board and verifying that the switch positions match the intended configuration for your installation. Next, check that the wired remote controller address is set to match the RMC address for that indoor unit. Once both settings are confirmed or corrected, cycle power to the unit to allow it to reinitialize. If the error persists after correcting the settings, the control board or remote controller may need further inspection.

A simple power reset will not permanently clear E157 if the underlying configuration issue has not been corrected. The error will return on startup because the system detects the mismatched settings each time it initializes. The SW03 switch positions and remote controller address must be properly configured before the fault will clear and stay cleared.