LG HVAC Error Code E606

E606 indicates a COM1/COM2 cross installation error on your LG HVAC system. It means the communication wires for the wired remote controller are connected to the wrong terminals, specifically that the F1/F2 and F3/F4 lines have been cross-connected. The system flags this fault because it cannot establish proper communication between the indoor unit and the remote controller with the wiring in that state.

The E606 error itself is not a safety hazard. It is a wiring configuration fault that prevents proper communication between the indoor unit and the wired remote controller. The system flags it to avoid operating under an unintended configuration. No refrigerant, electrical overload, or fire risk is associated with this specific fault code.

Since E606 is a wiring error rather than a parts failure, the cost is typically limited to a service call and labor charge, generally in the range of $75 to $200 depending on your location and the technician's rates. No replacement parts are normally required unless an inspection reveals that the communication cable itself is damaged and needs to be replaced, which could add a modest materials cost on top of labor.

Start by powering down the unit and locating the terminal block where the wired remote controller connects to the indoor unit. Verify that the communication cable is connected to the COM2 port, using terminals F3 and F4, not F1 and F2. If the wires are on the wrong terminals, move them to the correct positions, restore power, and check whether the error clears. If you are unsure about identifying the correct terminals, consult a qualified HVAC technician.

No, simply resetting the unit will not clear the E606 error. Because the fault is caused by a physical wiring error at the terminal block, the error will return immediately after a reset unless the cross-connected communication lines are corrected. The wiring must be properly reconnected to COM2 (F3 and F4) before the error will go away.