Mitsubishi City Multi Error Code List

Error 6600 means two devices on your VRF system share the same address. A configuration fault, not a broken wire — and usually cheap to correct.

Error 6602 is a transmission processor hardware fault. Unlike other M-NET codes, this one usually points at a board rather than wiring or configuration.

Error 6607 means part of your VRF control network stopped responding. What it means for your building, how urgent it is, and what it typically costs to fix.

Preliminary code 4320

Error 4220 covers inverter DC bus voltage faults. The detail code tells you whether the problem is your building's power supply or the inverter itself.

Preliminary code 4340

Error 4240 is overload protection. The compressor circuit drew high current too long — usually fighting a condition it could not overcome.

Preliminary code 4350

Error 4250 is the inverter overcurrent family. Its detail code tells you whether this is a board repair or a failed compressor — a big cost difference.

Error 1301 means low-side pressure dropped below its safe limit. On commercial VRF this often points to a refrigerant leak — the expensive scenario.

Preliminary code 1402

Error 1302 means refrigerant pressure exceeded its safe limit and the system shut down to protect the compressor. Left unresolved, it damages equipment.

Preliminary code 1202

Error 1102 means compressor discharge temperature ran too high. It is a compressor-protection shutdown, and the causes behind it are rarely trivial.

Preliminary code 1600

Error 1500 is refrigerant overcharge — there is too much refrigerant in the system. Usually the legacy of a previous top-up rather than a leak repair.

Error 4116 means a fan is not turning at the speed it was told to. On a rooftop unit this is one of the more common commercial VRF faults.

Preliminary code 4152

Error 4102 means the system lost a phase of its power supply. Usually electrical rather than mechanical, and it can damage the compressor if forced.

The 51xx codes are temperature sensor faults. Each number identifies a specific thermistor — cheap parts, but the labour to reach them varies enormously.

Error 2502 is a drain pump fault. The system stopped the affected unit to prevent water overflowing into your ceiling — which is the real risk here.

Error 5701 is a loose float switch connector. Trivial to fix — but the float switch is what stops condensate overflowing into your ceiling.

Error 7100 is a total capacity error — the indoor units connected exceed what the outdoor unit supports. A design or fit-out problem, not a failure.