CH93 - Communication between indoor and outdoor units is failing, often during test run or when outdoor power is missing.
LG says CH93 indicates a communication problem between the indoor and outdoor units. Shortly after installation or relocation, it commonly appears during test run when communication is unstable. LG also notes that on some models released after 2021, CH93 can appear if the outdoor unit is not receiving power.
Based on LG USA support articles for wall-mounted and related inverter split air conditioners; exact indicators and alternate code labels can vary by model.
Severity
High
Display
The code appears as CH93 on compatible models; on some newer installations it may be tied to separate power feeds for indoor and outdoor units.
Support first?
Often not
Models in range
Wall-mounted inverter split air conditioners, 2-in-1 heating and cooling air conditioners
What to do first
Start with these checks
- 1Verify the outdoor unit power plug is connected directly to a wall outlet if your model uses a separate plug.
- 2Check whether the AC breaker is on.
- 3Perform one 5-minute power reset if the code appeared during normal use.
Likely causes
What usually sits behind this code
Indoor and outdoor units are not communicating reliably.
Outdoor unit power plug is disconnected.
Air-conditioner breaker is switched off or outdoor unit is not receiving power.
Contact support
Contact customer support if any of these apply
- !CH93 persists after power and plug checks.
- !The breaker will not stay on or trips again.
- !The error started during installation, relocation, or test run.
- - LG says some models manufactured after 2021 changed communication-line configuration and require both indoor and outdoor units to be powered.
- - LG advises against using a power strip for the air conditioner.
Related codes
Nearby codes in this family
More ranges
More LG air-conditioner ranges
Source notes
Source and scope
Source: LG USA Support
LG says CH93 is an indoor-outdoor communication fault and, on some post-2021 models, can also indicate lost outdoor-unit power.
Last reviewed: 2026-04-19
Check only the plug and breaker positions that are safe to access. Do not attempt electrical testing or rewiring.