ErrorCodeDoctor
LG · Air Conditioner

LG Air Conditioner CH05 error code

Difficulty: Medium · Cost: $0–$150 · Duration: 5–10m

The CH05 error means your LG air conditioner's indoor and outdoor units have stopped communicating with each other. This can happen right after installation or relocation if the wiring between the units was not connected correctly, or during normal use if the power supply becomes unstable. The code may also appear as E0 or CH53 on some models. A power cycle resolves it in many cases but if the error keeps returning after resetting the unit will need a professional inspection. When this error is active the indoor unit indicator light will blink every 2 seconds.

Common causes

  • Incorrect or loose wiring between the indoor and outdoor units during installation or relocation
  • Unstable or fluctuating power supply disrupting communication between units
  • Communication wiring damaged or disconnected
  • Control board fault on either the indoor or outdoor unit
  • Circuit breaker for the outdoor unit is tripped while the indoor unit remains powered

How to fix it

  1. 1

    Unplug the power cord or turn off the circuit breaker and wait 5 minutes

  2. 2

    Restore power and check if the error has cleared

  3. 3

    If the error appeared right after installation check that all wiring between the indoor and outdoor units is connected correctly and securely

  4. 4

    Make sure the circuit breaker for the outdoor unit has not tripped

  5. 5

    If CH05, E0, or CH53 keeps returning after a power cycle contact a technician to inspect the communication wiring and control boards

Related LG Air Conditioner error codes

1

CH04

The indoor unit is not draining condensate water properly

easy
2

CH07

Two connected units are set to conflicting operating modes

easy
3

CH38

The air conditioner is low on refrigerant gas

hard
4

CH54

A reverse phase or abnormal power supply was detected

medium

CH05 error — frequently asked questions

What does the CH05 error mean on a LG air conditioner?

Communication between the indoor and outdoor units has been lost

What causes the CH05 error?

The CH05 error is usually caused by: Incorrect or loose wiring between the indoor and outdoor units during installation or relocation; Unstable or fluctuating power supply disrupting communication between units; Communication wiring damaged or disconnected; Control board fault on either the indoor or outdoor unit; Circuit breaker for the outdoor unit is tripped while the indoor unit remains powered.

Can I fix the CH05 error myself?

It's possible for a moderately handy person, but budget 5–10m and expect some disassembly.

How much does it cost to fix the CH05 error?

Fixing the CH05 error on a LG air conditioner typically costs $0–$150, depending on parts and whether you do it yourself or hire a technician.

Is it safe to keep using my air conditioner with the CH05 error?

In most cases yes, but it's best to address the CH05 error soon — see the fix steps below to resolve it.