Fault Codes / Mitsubishi Electric / 0403

ME

Mitsubishi Electric 0403

High

City Multi — Serial / panel communication error.

Mitsubishi Electric 0403: Serial / panel communication error. This fault noticeably affects operation.

Possible causes

Control PCB ↔ INV/fan board link loose/faulty.
Noise / PCB faulty.

Check steps

Check CN4A/CN4B (control) & CN80 (fan), CN2 (INV).
Power off: reseat connectors, check PCB.

Affected parts

Control-PCB
INV-Board

Safety note

230/400V — isolate power.

Source: Mitsubishi Electric City Multi Fault Code List (offiziell, 2024-10)

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