LG Air Conditioner Error Code E590

E590 indicates an EEPROM checksum error between the outdoor unit's MAIN control board and the INVERTER control board. The two boards compare stored configuration data during operation, and when those values do not match, the system triggers E590 and shuts down. This is a hardware-level fault within the outdoor unit that requires hands-on diagnosis of the inverter PBA and related wiring.

No. When E590 is active, the unit has already stopped operating to protect itself from running on mismatched configuration data. Attempting to force the unit to run while this fault is present could risk damage to the compressor or inverter drive components. The system should remain off until the fault is diagnosed and corrected.

Repair costs depend on what component needs to be replaced. If only a wiring harness or connector is at fault, costs are relatively low and primarily labor-based. If the outdoor inverter PBA requires replacement, parts and labor together can range from $200 to $600 or more depending on the specific model and local labor rates. Getting a diagnostic visit from a licensed HVAC technician is the most reliable way to get an accurate estimate.

Resolving E590 requires inspecting and potentially replacing components inside the outdoor unit, including the inverter printed board assembly. While a knowledgeable DIYer can check wiring harness connections and reseat connectors, board replacement and deeper diagnosis typically require technical experience and familiarity with inverter-driven systems. Working inside the outdoor unit also involves exposure to high-voltage DC bus capacitors, which can remain charged even after power is disconnected.

A power reset may temporarily clear the error display, but E590 is caused by a hardware condition, specifically a checksum mismatch stored in the EEPROM. If the underlying issue with the inverter PBA or its wiring has not been resolved, the error will return when the unit attempts to start up again. A reset alone is not a fix.