LG Air Conditioner Error Code 86

Error code 86 indicates that the outdoor unit's main PCB cannot communicate with its EEPROM chip, or that the EEPROM is missing entirely. The EEPROM stores model-specific configuration and operating parameters that the main microcontroller requires to function. The system stops operating and displays this code to prevent running with invalid or absent settings. The first step is to check whether the EEPROM chip is correctly installed on the outdoor unit control board.

No. The system will not operate normally with error 86 active because it cannot read its required configuration data. Attempting to force operation without resolving the underlying fault could result in improper system behavior. The unit should remain off until the EEPROM communication issue is diagnosed and corrected.

If only the EEPROM chip needs to be replaced or reseated, costs are generally low, potentially ranging from minimal labor charges up to around $100 to $200 depending on service rates. If the entire outdoor unit main PCB requires replacement, parts and labor costs can range from $200 to $600 or more depending on the model and local service pricing. Getting a diagnostic visit from a certified technician will provide a more accurate estimate for your specific unit.

If the cause is a loose or incorrectly oriented EEPROM chip, a knowledgeable DIYer comfortable working with circuit boards can reseat the chip after disconnecting power to the unit. However, accessing the outdoor unit PCB requires removing panels and working near high-voltage components, so caution is essential. If the chip is correctly seated and the error persists, the EEPROM or main PCB likely needs professional replacement.

A power reset may temporarily clear the error display, but the fault will return immediately on the next startup if the underlying EEPROM issue is not resolved. The error is generated during the initialization sequence when the MICOM attempts to read the EEPROM, so it will reappear each time the unit powers on until the root cause is addressed.