Mitsubishi Electric aircon PCB repair in Singapore
A Mitsubishi Electric board code says which circuit reported the fault, not whether the board itself has failed. We test the indoor PCB, outdoor PCB and inverter or driver stage separately, explain what failed and quote after diagnosis.
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Signs your Mitsubishi Electric aircon needs a PCB check
These symptoms can involve a control board, but they can also come from wiring, a sensor or another part connected to the board.
The unit has power but will not start
Lights or the controller may still respond while the indoor unit, outdoor unit or both refuse to run normally.One room or the whole system stops responding
The pattern across rooms helps separate an indoor-board problem from an outdoor or shared communication fault.A communication or board-related error appears
A Mitsubishi Electric code, blinking light or repeated restart gives us a useful starting point, but it still needs electrical testing.
Examples of Mitsubishi Electric systems we check
Starmex R32 single-split systems
Starmex R32 multi-split and MSXY-FN indoor units
PLY cassette, PEY ducted and City Multi systems, with scope confirmed from the exact family
Model not listed
Send photos of the indoor and outdoor model labels, plus the error code or a short video of the symptom.
A board-related code does not always mean a failed PCB
Before ordering model-specific electronics, we check three problems that can make a healthy board appear faulty.
Power or wiring fault
Loose terminals, a damaged interconnect or unstable supply can produce board and communication errors.Sensor or connected load
A shorted thermistor, motor or valve can pull down a healthy board or make its input look incorrect.Inverter power stage
On inverter systems, the main control PCB and the IPM or driver circuit are tested as separate failure points.
We check the power supply, communication wiring, sensors, connected loads, indoor and outdoor boards, and inverter drive where fitted. How a job runs, from first message to booking.
What is different on Mitsubishi Electric systems
Mitsubishi Electric uses both display codes and lamp patterns across its families. We match the observed display to the model before deciding whether the fault sits indoors, outdoors or in communication wiring.
Mitsubishi Electric error codes related to PCB problems
Open the group that matches where the code appeared on your unit.
Indoor unit or controller20 guides
- 0095Warning that a metering device may be damaged
- 0100Connected equipment abnormality
- 6601M-NET communication polarity has not been established
- 6602M-NET transmission-processor hardware error
- 6603M-NET transmission line is busy; M-NET transmission bus busy
- 6604No M-NET ACK (06H) because of a communication-circuit error
- 6605No M-NET response frame was received
- 6606M-NET transmission-processor communication error; Communication error with the M-NET transmission processor
- 6607No M-NET acknowledgement was returned; M-NET no-acknowledgement communication error
- 6608No M-NET response frame was returned; M-NET no-response communication error
- 6920Controller communication no-response error
- 6922Controller communication received-frame ID error
- E0Remote-controller receiving error; Remote controller transmission error
- E1Remote-controller control-board memory error; Remote controller control board error
- E2Remote-controller clock-function error
- E3Remote-controller transmitting error
- E4Indoor controller cannot receive the remote-controller signal; Remote-controller signal receiving error
- E5Indoor controller cannot transmit on the remote-controller path; Remote-controller signal transmitting error
- E6 / E7Indoor-outdoor communication receiving error; Indoor-outdoor communication transmitting error
- FB / FbIndoor controller memory or control-system error; Indoor control-system or memory error
Outdoor unit3 guides
Whole-system faults15 guides
- 6201PZ-62DR remote-controller circuit-board failure
- 6202PZ-62DR remote-controller clock or circuit-board failure
- 6801PZ-43SMF-E remote-controller communication error
- 6831PZ-62DR remote-controller no-reception communication error; Signal reception fault at the MA controller with no signal received
- 6832PZ-62DR remote-controller synchronization-recovery communication error; Signal transmission synchronization fault at the MA controller
- 6833PZ-62DR remote-controller communication hardware error; Signal transmission hardware fault at the MA controller
- 6834PZ-62DR start-bit detection or leader-follower communication error; Signal reception start-bit detection fault at the MA controller
- E8Indoor/outdoor communication receiving error; Serial signal
- E9Indoor/outdoor communication receiving error; Indoor-outdoor unit communication error
- ECIndoor/outdoor communication receiving error
- U6Compressor overcurrent or power-module abnormality
- U8Outdoor fan protection stop
- U9 / UHPower-voltage, synchronous-signal, or current-sensor abnormality
- UFCompressor locked or overcurrent interruption
- UPCompressor overcurrent interruption
Codes that depend on the exact model22 guides
- 04 / LED 6xSerial signal
- 06 / LED1 lit, LED2 6xZero cross detecting circuit on outdoor control P.C. board
- 06 / LED1 lit, LED2 7xNonvolatile memory data
- 09 / LED1 lit, LED2 11xCommunication error between P.C. boards
- 10 / LED1 lit, LED2 12xZero cross detecting circuit on outdoor power P.C. board
- 13 / LED1 lit, LED2 15xRelay operation
- 24 / LED1 lit, LED2 11xCommunication between P.C. boards protection
- 25 / LED1 lit, LED2 12xZero cross detecting circuit on outdoor power P.C. board
- 0403Serial or panel communication fault involving the indoor or auto-filter-cleaning control boards
- 4225Control power-supply fault
- 4226Low bus voltage at startup
- 5305Fan-board current-sensor fault
- 5306Fan-board current-sensor circuit fault
- 7110Connection-information signal transmission or reception fault
- EdSerial communication error between outdoor boards or M-NET communication error
- EFCheck code is not defined
- FR03 / recall upper lamp 3xSerial signal from outdoor unit not received
- FR12 / recall upper lamp 12xIndoor control PCB nonvolatile memory read fault
- PUY-WIRINGMiswiring of indoor/outdoor connecting wire, excessive indoor-unit count, or startup time over
- Starmex 4 blinksIndoor control system
- Starmex 7 blinksOutdoor control system
- Starmex continuous blinkMiswiring or serial signal
Codes can mean different things across model and system families. Every code is in the full lookup for this brand. Last reviewed 2026-08-21.
Is Mitsubishi Electric PCB repair worth it?
Parts and timing
Starmex parts for current and recent residential families are generally available. Older commercial or discontinued boards require an exact model and part-number check.Our recommendation
PCB repair is usually sensible when the rest of the system is healthy, the exact board revision is available and testing has ruled out wiring, sensors and connected loads. Mitsubishi Electric systems commonly have a service life of Starmex residential: 8–12 years. For a system starmex over 12 years, parts sourcing becomes harder for older Starmex models. Major component failures usually favour replacement, especially if efficiency has noticeably dropped.
If replacement makes more sense, we compare the repair quote with a suitable new system. See our aircon system replacement process.
Other Mitsubishi Electric repair checks
If testing rules out this part, these are the next checks on the same system.
Workmanship warranty
We stand behind the repair we carry out, and we are straight about the part of the cover we do not set ourselves.
Labour
30-day workmanship warranty. If the same fault returns from our repair, we come back and the labour is on us, with no second diagnostic visit fee.
Parts
Parts carry the distributor's warranty for that component, so the term varies by part. We tell you both terms before you approve the work.
Frequently asked questions about Mitsubishi Electric PCB repair in Singapore
What are the signs of a Mitsubishi Electric PCB problem?
How do you confirm a Mitsubishi Electric PCB fault?
Is a Mitsubishi Electric error code enough to order the PCB?
Should I repair or replace my Mitsubishi Electric aircon?
We cover all of Singapore. Find aircon services in your area.
Describe your situation
Tell us what’s going on. Symptoms, setup, photos, anything we should know. We’ll assess and come back with the right next step.