LG Air Conditioner Error Code E199

E199 means the pipe check operation was not performed after the system completed auto addressing during installation. Auto addressing assigns communication addresses to each indoor unit, and pipe check is the required follow-up step that verifies refrigerant circuit connections. This is a commissioning status code, not a component failure. It clears once the pipe check is successfully completed by pressing the K1 button on the outdoor display PCB.

A simple power reset will not clear E199 because the code is tied to an incomplete commissioning step, not a temporary fault. The system will continue to display E199 after each restart until the pipe check operation is physically initiated and completed using the K1 button on the outdoor display PCB. Only completing the required commissioning step resolves the fault.

If E199 is simply due to a skipped pipe check step, the cost is limited to a service call fee for a technician to visit the site and press the K1 button to initiate the operation, typically in the range of $75 to $150 depending on location and provider. If the pipe check reveals an underlying refrigerant circuit issue such as cross-piping or low charge, additional diagnostic and repair costs will apply and can range from $150 to $500 or more depending on the scope of the problem.

To resolve E199, a technician needs to press the K1 button on the outdoor unit's display PCB to initiate the pipe check operation. This step must be performed on-site at the outdoor unit and cannot be triggered remotely or through the indoor unit controls. If the pipe check completes successfully, the E199 code will clear and the system can enter normal operation.

E199 itself does not indicate a refrigerant leak, electrical hazard, or immediate safety risk. It signals that commissioning is incomplete, which means the system may not operate correctly or efficiently until the pipe check is done. However, running the system long-term without completing the pipe check can lead to unverified piping connections, which could mask underlying installation issues.