LG CH57

High

Multi V5 — Communication error between outdoor unit main PCB and inverter PCB (Master: 571, Slave 1: 572, Slave 2: 573).

LG CH57: Communication error between outdoor unit main PCB and inverter PCB (Master: 571, Slave 1: 572, Slave 2: 573). This fault noticeably affects operation.

Possible causes

Poor connection between main and inverter PCBs, or communication wire noise interference
Damaged outdoor unit main PCB or inverter PCB

Check steps

Verify communication cable connections and inspect wiring for damage or noise sources
Reset power and observe; if the error persists, replace the inverter PCB, then the main PCB if still unresolved

Affected parts

Outdoor unit main PCB
Inverter PCB
Communication wiring

Safety note

Disconnect power supply before working on the PCBs or wiring.

Source: LG resmi servis kilavuzu (bagimsiz cift-dogrulandi) — LG Multi V5 Service Manual (ManualsLib doc #1483751), Error No. 57, page 170: "Communication error between outdoor unit main PCB and inverter PCB" (Master: 571, Slave 1: 572, Slave 2: 573). Cross-verified against: (1) the manual's own error-numbering convention on page 126 (X1=master/X2=slave1/X3=slave2 pattern, e.g.…

Reviewed by Anıl Güzeldemir — in the refrigeration machine room since 2006, developer of Enthalio.

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