LG Air Conditioner Error Code CH93

CH93 is a communication error indicating that the indoor and outdoor units of your LG air conditioning system have lost contact with each other. The system depends on a dedicated communication wire to exchange operational data, and CH93 appears when that signal is interrupted or lost. It is an alternate code for a communication fault and may appear alongside similar codes depending on system configuration. The root cause is typically a wiring or connection problem rather than a failed circuit board.

No. When CH93 is active, the system has typically shut down because the indoor and outdoor units cannot safely coordinate operation. Attempting to force the unit to run without resolving the underlying communication fault could cause improper compressor or fan operation. The system should remain off until the wiring fault is diagnosed and corrected.

Repair costs vary depending on the root cause. If the fix involves tightening loose connections or cleaning corroded terminals, labor charges alone may range from around $75 to $150 depending on your location and the technician's rates. If the communication wire run between the indoor and outdoor units needs to be replaced, total costs including parts and labor could range from $150 to $400 or more depending on the length of the wire run and accessibility. Control board replacement, if found to be necessary, would add significantly to that estimate.

Some basic checks, such as visually inspecting wiring connections for obvious looseness or damage, are accessible to a knowledgeable DIYer. However, properly diagnosing this code requires measuring resistance on the communication line and checking voltage integrity on the power wires, which requires a multimeter and familiarity with AC wiring safety practices. If any wiring inside the outdoor unit or along the line set needs to be repaired or replaced, it is strongly recommended to have a licensed HVAC technician perform the work.

A power cycle reset may temporarily clear the CH93 code if the fault was caused by a momentary voltage spike or transient interference on the communication line. However, if the underlying cause is a physical wiring problem such as a damaged wire, corroded terminal, or loose connection, the code will return shortly after the unit restarts. A proper repair of the communication wiring is required for a lasting fix.