CH53

Communication Error (Outdoor to Indoor)

Home Appliance Error Codes LG Split AC

Can you still use it? With care until repaired

Who can fix it? Needs a technician

Typical repair time 30 minutes – 3 hours

Typical cost SAR 100 to 2,500

What it means

This code appears on LG inverter split air conditioners and on LG ducted and cassette units that use CH codes. It means a communication fault between the outdoor and indoor units, detected on the outdoor side: signals are not arriving or arrive corrupted. The compressor stops until communication is restored. Its exact use differs slightly between LG single-split, multi and ducted systems, and the same code can mean something else on other brands.

Models covered: LG inverter split air conditioners (e.g. Dual Inverter) and LG ducted/cassette units that use CH codes; the code shows as CH plus a number on the display or as LED blinks.

Symptoms4

CH53 shows and cooling stops.
It may appear after some running time, clear, then return on and off.
On systems with several indoor units, one or more of them may stop.
It may appear alongside, or instead of, communication code CH05 depending on the model.

Possible causes5

Loose or corroded communication terminals at the indoor or outdoor terminal block.
Damaged communication cable, or wires in the wrong order after installation or service.
On multi systems: an indoor unit wired to the wrong port or set up incorrectly.
Electrical noise from nearby power cables or poor earthing.
Faulty communication circuit on the indoor or outdoor PCB.

How to diagnose5

Switch off the breaker for several minutes, then restart.
A technician checks the communication terminals at both units for correct order and tightness per the LG diagram.
Check cable continuity and insulation, and make sure it does not run alongside power cables that cause noise.
On multi systems, confirm each indoor unit is wired to its correct port.
Watch the indicators on both boards; if wiring is good, find the failed board by testing or substitution.

How to fix6

Tighten, clean and correct the order of the communication terminals.
Replace a damaged communication cable and route it away from power cables.
Correct indoor unit port wiring on multi systems.
Repair the earth connection.
Replace the failed PCB (indoor or outdoor) based on the tests.
Run the system for a long period and confirm the code does not return.

Repair cost

0–200

200–600

600–1,500

1,500+

In Saudi riyals; the highlighted part is the expected range for this fault.

Most cases are fixed by repairing terminals or the cable at low cost; the top of the range is a new outdoor PCB.

Prices are rough estimates including the part and the technician’s fee, and vary with brand, model and part source.
Prices last updated: September 2026

Frequently asked questions

What is the difference between CH05 and CH53?

Both are communication errors between the units, but CH05 is usually detected by the indoor unit and CH53 by the outdoor unit. The checks are similar and start with the cable and terminals.

Does CH53 show up after moving the AC?

Often, yes. Reconnecting the communication cable in the wrong order or leaving a loose terminal is one of its most common causes.

This guide is for information only and does not replace an inspection by a qualified technician. If the fault involves brakes, steering, engine temperature, electrics or refrigerant, do not attempt the repair yourself.

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