LG Air Conditioner Error Code E205

E205 indicates a communication error across all printed board assemblies (PBAs) within the outdoor unit's C-Box. This means the control boards inside the outdoor unit have lost the ability to communicate with each other. The fault is typically caused by a loose or damaged communication connector or cable, or in some cases a failed inverter PCB. A technician should start by inspecting the CN32 and CN31 connectors on the inverter PCB.

No, you should not continue operating the unit while E205 is active. A total communication failure between the outdoor unit control boards means the system cannot properly coordinate operation, which could lead to uncontrolled component behavior or further damage. Power the unit off and leave it off until the fault is diagnosed and resolved.

Repair costs vary depending on the root cause. If the fix is simply reseating a loose connector, the cost may be limited to a service call fee, typically in the range of $75 to $150. If the communication cable needs replacement, parts and labor could run $150 to $350. A failed inverter PCB is the most expensive scenario, with parts and labor potentially ranging from $300 to $700 or more depending on the model and part availability.

Some causes of E205 are accessible to a knowledgeable DIYer, such as checking and reseating the communication connectors on the inverter PCB inside the outdoor unit. However, working inside the outdoor unit involves exposure to high-voltage components, so this should only be attempted after disconnecting power at the disconnect and breaker. If the connectors appear secure and undamaged, further diagnosis involving the PCB or internal wiring typically requires a qualified technician.

A power reset may temporarily clear the error display, but E205 will return if the underlying communication fault is still present. If the connectors are loose, reseating them before resetting may resolve the issue. However, if the cable is damaged or a PCB has failed, the error will reappear as soon as the unit attempts to resume normal operation.