On the covered LG air conditioner, CH 93 means a communication problem between the indoor and outdoor units — LG's own wording. LG states CH93 typically occurs during the test run when communication is unstable, and that on models released after 2021 it can also appear for another reason. First, note whether the error followed installation or relocation.
Try in this order
0 of 8 completedWhat to do first
ReversibleNote whether the error followed installation or relocation.
Correct only the documented fault domain
ReversibleHave the communication line checked; If the code appeared shortly after installation or relocation, LG directs you to the installing technician rather than to general service..
Reset both breakers
ReversibleIf the outdoor unit's breaker tripped, switch the indoor unit's breaker off too for 5 minutes, then turn both on at the same time.
Check the communication wiring
ReversibleLG's help library says to confirm the communication wires are correctly connected and the Live and Neutral are the right way round. Loose, damaged or mismatched wiring between the two units is the usual cause.
Note when it started
ReversibleLG says CH93 usually shows during a test run or soon after installation, so tell the installer if the unit is new.
Switch off both breakers
ReversibleTurn off the indoor unit's breaker as well as the outdoor one for five minutes, then turn both on together.
Look at the outdoor unit
ReversibleWith the power off, check that the outdoor unit's cover is closed and that nothing has chewed or loosened the cable between the units.
Call the installer for the line
ReversibleRechecking or rewiring the communication line is for the installer or a licensed technician.
Evidence ledger
Sources behind this answer
Exact questions
Common questions about “LG air conditioner code CH 93”
What does CH 93 mean on a LG air conditioner?+
a communication problem between the indoor and outdoor units — LG's own wording. LG states CH93 typically occurs during the test run when communication is unstable, and that on models released after 2021 it can also appear for another reason.
Can a power surge cause a communication error on an LG air conditioner?+
A surge or outage can leave the outdoor board unresponsive. Switching both breakers off for 5 minutes and back on together is the first fix.
Does CH93 appear on LG window air conditioners?+
No. CH93 is a communication fault between an indoor and an outdoor unit, so it belongs to split and multi-split systems; a window unit is one piece and has no link to lose.
Can I check the communication wiring myself?+
Only with the power off at both breakers, and only to look for a loose or damaged connection. Rewiring the line between the units is a job for the installer or a licensed technician.
What if CH93 appears only in very hot or humid weather?+
Heat can expose a weak connection or a marginal board. Note the conditions when it appears and tell the technician, since it narrows down the cause.
Why do I have to switch off both breakers for CH93?+
So the indoor and outdoor boards restart together and try to talk to each other from a clean start.
Can a power surge trigger CH93?+
A surge can upset the boards or trip the outdoor supply, so it is worth telling the technician if the code began after a storm or a power cut.