Mitsubishi Electric Air Conditioner Error Codes List: Every Code Explained

Every Mitsubishi Electric air conditioner error code we could verify against Mitsubishi Electric's own documentation — what it means, what usually causes it, and the first fix to try — in one table. Codes differ between model series, so treat your model's tech sheet as the final word.

How to read and retrieve error codes on Mitsubishi Electric air conditioners

Mitsubishi builds the diagnosis into the remote. The wired controller shows the two-character check code as text, with IC (indoor unit) or OC (outdoor unit) telling you which side reported and the unit number telling you which unit on a multi system. The wireless self-check speaks in two dialects the manuals call Output Pattern A and Output Pattern B: Pattern A is errors detected by the indoor unit (the P and indoor-E families), Pattern B is errors detected by the outdoor unit (the U family and E9), and the two patterns are told apart by the lamp rhythm — in Pattern A the long lamp pulse is about 2.5 seconds, in Pattern B about 3 seconds with short 0.5-second pulses — as well as by which family the counted code belongs to. The outdoor unit adds a third witness: its controller board's LED display carries model-specific detail (the PUY table, for example, pairs codes with green/red LED blink counts), and the service documents repeatedly end a Pattern B symptom with 'for details, check the LED display of the outdoor controller board'. Practical rule: record code, IC/OC, unit number and pattern together — 'U2, Pattern B' is a diagnosis, while a bare blink count copied from a forum is a rumour, because the per-code blink counts differ between Mitsubishi's own documents.

The complete Mitsubishi Electric air conditioner error code list

How to reset / clear error codes on Mitsubishi Electric air conditioners

A Mitsubishi check code is a condition report, not a latch with a ritual clear. On a wired remote controller the self-check is run with the CHECK button (press CHECK twice, set the address with TEMP if system control is used, read the code and the unit number together), and a stored code is cancelled from the self-check result screen by pressing ON/OFF twice within 3 seconds while the address blinks. On a wireless remote the self-check starts by holding MENU for 5 seconds until CHECK lights, selecting the refrigerant address with TEMP and pressing SET — the indoor unit then answers with beeps and OPERATION INDICATOR blinks. Clearing the record never repairs anything: a code whose condition still stands is written again at the next self-test. The one genuine reset is power: off at the breaker/isolator for several minutes — both units, since a split's indoor and outdoor sections usually share an isolator — then back on and a full run cycle observed. A code that survives that, or returns within days, is a confirmed present fault with a part or a wire behind it. CITY MULTI faults reset the way Mitsubishi's own list prescribes per code — several transmission faults (6607/6608) start with all units powered off for 5 or more minutes — and VRF resets are installer work, not owner work.

How to diagnose any Mitsubishi Electric air conditioner code

Work the problem in this order — and stop where refrigerant, compressors or mains wiring begin, because those are licensed work: (1) record the code exactly as displayed, including whether it came from the indoor display, the wired/wireless remote check mode, or an LED pattern on the outdoor unit — the three are different reports; (2) check the homeowner basics first: the air filter (a matted filter ices coils and imitates sensor and refrigerant faults), the condensate drain and float switch, the outdoor coil clear of leaves and debris, and both breakers fully on; (3) power-cycle once at the breaker, then run the mode the code interrupted and watch the sequence — indoor fan, outdoor fan, compressor start — because the stage that never starts names the fault family; (4) on mini-splits, retrieve the stored check code with the remote's diagnosis function before clearing anything, and write down the full code including its letter family; (5) a code that returns in the same mode is an active fault. Refrigerant charge, sealed-system and board-level work is professional work — an undercharged system re-iced after a reset is being damaged, not cured.

Two companies, one name: why Mitsubishi Electric codes must never be read with Mitsubishi Heavy Industries tables

The single most expensive mistake in Mitsubishi air-conditioning diagnosis costs nothing to make: searching the model, finding a clean code table, and trusting it — when the table belongs to the other Mitsubishi. Mitsubishi Electric and Mitsubishi Heavy Industries are separate companies that both sell split air conditioners, and their code systems overlap just enough to be dangerous. Both use P1 for an intake sensor and P4/P5 around drains, so a borrowed table looks right for the first three codes you check. Then it quietly diverges. Heavy Industries publishes P3 as a system/transmission error and P7 as a system/address error; no Mitsubishi Electric document contains either code — an Electric unit reporting through its self-check has no P3 or P7 to give, and a technician chasing a Heavy Industries P3 procedure on an Electric unit is working on a fault the unit never reported. The Electric system has its own grammar instead: Pattern A codes detected by the indoor unit, Pattern B codes detected by the outdoor unit, the U family reserved for outdoor events and protections, and CITY MULTI speaking an entirely separate four-digit language on VRF systems. The defence is boring and total: identify the manufacturer from the rating plate (Electric's manuals carry the Tokyo Building, Marunouchi head-office address and document codes like VG79F112H01), identify the platform (Mr. Slim, M-Series or CITY MULTI), and only then open a table. Every code on this page can be pointed to in a named Mitsubishi Electric document. If a code list cannot name its document, it is not a Mitsubishi Electric list — it is a collage, and collages that mix two companies' tables will eventually hand you a confident, detailed, completely wrong repair.

Pattern A and Pattern B: how a Mitsubishi tells you which half of the system is talking

A Mitsubishi split is two machines sharing one refrigerant circuit, and its self-check is organised around that fact. When you run the wireless remote's self-check — hold MENU for five seconds, choose the refrigerant address, press SET — the indoor unit answers with beeps and operation-lamp blinks in one of two rhythms, and the rhythm is the first half of the diagnosis. Output Pattern A means the error was detected by the indoor unit: the P family (its sensors, its drain, its fan, its board) and the indoor-side communication codes. Output Pattern B means the error was detected by a unit other than the indoor unit — in practice the outdoor unit: the whole U family of protections and power faults, and E9, the outdoor-detected twin of the indoor-detected E6/E7 communication error. The manuals even separate the patterns physically, with different long-pulse durations in the lamp pattern. This structure does real diagnostic work. E6 and E9 are the same broken conversation reported from opposite ends of the wire, and knowing which end is complaining tells the technician where to stand first. A Pattern A P6 (freeze/overheat protection) is the indoor coil's own testimony, so the investigation starts at filters and airflow; a Pattern B U2 is the outdoor unit reporting a discharge temperature, so it starts at charge, valves and the outdoor fan. On a wired remote the same information arrives as text plus an IC or OC marker and a unit number — record all of it. The pattern, the code and the unit number together are the complete report; any one of them alone is a third of a diagnosis, and third-diagnoses are how good compressors get replaced for bad thermistors.

CITY MULTI is not a big Mr. Slim: the four-digit system, preliminary codes, and what the brackets mean

CITY MULTI, Mitsubishi Electric's VRF platform, reports faults as four-digit codes — 1102, 1302, 5201, 6607 — and the worst thing a reader can do is treat those numbers as an extension of the Mr. Slim two-character table, or worse, divide them by a hundred and look the remainder up as a P-code. The four-digit system is its own language with its own grammar. The thousands digit is a neighbourhood: 1xxx is the refrigerant circuit's temperatures and pressures (1102 discharge temperature, 1301 low pressure, 1302 high pressure, 1500 overcharge), 2xxx is water and drain (2500 leakage, 2502 drain pump, 2503 drain sensor), 4xxx is the inverter and power stage (4230 heatsink overheat), 5xxx is sensors (5201 high-pressure sensor, 5202 low-pressure sensor), 6xxx is transmission and addressing (6600 overlap, 6607 no ACK, 6608 no response) and 7xxx is system configuration (7100 total capacity). Woven through it is a second layer the Mr. Slim table does not have: preliminary codes, shown in brackets in Mitsubishi's list — 1202 is the preliminary warning of 1102, 1402 of 1302, 1600 of 1500 — the system telling you a fault is forming before it commits to the full error stop. And in the PUMY list Mitsubishi prints a third layer: the two-digit equivalent in brackets beside many four-digit codes (5201 carries '(F5)', 2502 carries '(P5)', 6600 carries '(A0)'), because a CITY MULTI indoor unit can surface the same event in the small code its local display speaks. Those brackets are Mitsubishi's own cross-reference, valid exactly where printed — they are not a licence to convert any four-digit code by analogy. A CITY MULTI fault is specialist work by design: networked units, shared transmission lines with published length and wire limits, and addressing that must be unique across the system. The owner's entire job on a CITY MULTI code is to record it completely — code, preliminary code if shown, and the address of the unit that reported it — and hand that, untouched, to the VRF contractor.

Less common and model-specific codes

Search data shows owners also meet these codes on Mitsubishi Electric air conditioners: E8, F1, F2, F4, F7, F8, F9, FA. They are not part of the core code list Mitsubishi Electric publishes for most models — several are series-specific, abbreviated display readings, or codes carried over from a sister platform — so we do not publish meanings for them rather than guess. Treat them by symptom: note what the machine was doing when the code appeared (filling, draining, heating, spinning), run one full power cycle (5 minutes off), and if the code returns, match the symptom to the closest documented family in the table above and check the tech sheet stored inside your machine for the model-specific definition.

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Facts on this page were checked against manufacturer documentation: manuals.plus · manuals.plus · manuals.plus · www.MitsubishiElectric.com.sg · anyflip.com · manualsdump.com