Mitsubishi Electric E7

High

Mr. Slim (PLY-ZM/PLY-M/PEY-M/PCY-M serisi ve PUY-P/PUY-M serisi) — Indoor/outdoor unit communication error (signal receiving or transmitting error), detected by indoor or outdoor unit

Mitsubishi Electric E7: Indoor/outdoor unit communication error (signal receiving or transmitting error), detected by indoor or outdoor unit This fault noticeably affects operation.

Possible causes

Indoor/outdoor connecting wire loose or damaged
Electrical noise entering the transmission wire or power supply

Check steps

Check that the indoor/outdoor connecting wire is connected correctly
Turn power off and on again, then re-check the error

Affected parts

İndoor/outdoor connecting wire
Indoor PCB
Outdoor PCB

Safety note

Disconnect power supply before working on the wiring.

Source: Mitsubishi Electric resmi servis kilavuzu (bagimsiz cift-dogrulandi) — Mitsubishi Electric Mr. SLIM Indoor Unit - Malfunction-diagnosis method at maintenance service (PLY-ZM50EA / PLY-M60,80,100,125EA / PEY-M50,60,80,100,125JAL / PCY-M125KAL), rev. 20241024, page 3 (Output pattern A table): "E6, E7 | Indoor/outdoor unit communication error". Cross-checked against PUY-P42,48,125VKA.TH /…

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

Look up in Enthalio →

Related fault codes

Indoor/outdoor communication error.E6 High discharge temperature — compressor overheU2 Outdoor thermistor fault (open/short).U4 Pipe temperature error (often defrost/thermistP8 Serial / panel communication error.0403 Discharge temperature fault (too high).1102