Fujitsu wall-mounted units don’t show error codes on a screen. They blink. If the Operation and Timer lamps on your indoor unit are flashing while the Economy lamp blinks fast, the unit has stopped on a fault, and the number of flashes is the code. This guide shows how to read Fujitsu mini split error codes from the lamps, what each one means, and which ones you can check yourself.
Every code below comes from Fujitsu General America’s own mini split troubleshooting guide and Fujitsu’s operating manuals. One lamp pattern that worries a lot of owners isn’t an error at all, so check that first.
Table of Contents
First, make sure it’s really an error
Two lamp patterns look alarming but are normal:
- Only the Operation lamp blinks, in heating mode. The unit is defrosting its outdoor coil. Fujitsu’s manual says the Operation lamp flashes during automatic defrost, which lasts up to 15 minutes. Wait it out.
- Only the Timer lamp blinks. According to Fujitsu, this means the power was interrupted and the timer settings were lost. Set the timer again, or cancel it, and the lamp stops.
A real fault looks different: the Operation and Timer lamps blink a set number of times while the Economy lamp blinks fast. Fujitsu’s instruction in that case is to stop the unit and contact service, but a reset and a few simple checks come first.
How to read Fujitsu mini split error codes from the lamps
Count the flashes in each cycle. The Operation lamp gives the first digit and the Timer lamp gives the second. For example, 1 flash on Operation and 1 on Timer is code 11; 4 flashes and 2 flashes is code 42. Ten flashes on the Operation lamp stands for the letter A, so 10 and 1 is code A1. If you have a wired wall controller, it shows the same code directly as a number.
| First digit (Operation lamp) | Where the problem is | Can you check it yourself? |
|---|---|---|
| 1 and 2 | Communication and setup | Partly: power to both units |
| 3, 4 and 5 | Indoor unit: board, sensors, fan, drain | Partly: filters, airflow, drain |
| 6 | Outdoor unit circuit boards | Only the reset |
| 7 | Outdoor unit temperature sensors | No, technician |
| 8 and 9 | Current, pressure, compressor, outdoor fan, reversing valve | Partly: clear the outdoor unit |
| 10 (A) | Temperature and pressure protection | No, technician |
Full list of Fujitsu mini split error codes
| Code | Flashes (Operation / Timer) | What it means |
|---|---|---|
| 11 | 1 / 1 | Serial communication error between indoor and outdoor units |
| 12 | 1 / 2 | Wired remote controller communication error |
| 15 | 1 / 5 | Automatic airflow adjustment error (ducted units) |
| 18 | 1 / 8 | External communication error |
| 23 | 2 / 3 | Combination error: indoor unit type doesn’t match |
| 26 | 2 / 6 | Address setting error in the wired remote system |
| 29 | 2 / 9 | Number of connected units error (wired remote) |
| 32 | 3 / 2 | Indoor unit board model information error |
| 33 | 3 / 3 | Indoor fan motor power consumption error |
| 35 | 3 / 5 | Manual auto switch held down for more than 60 seconds |
| 39 | 3 / 9 | Indoor fan motor power supply error |
| 3A | 3 / 10 | Indoor unit communication circuit error (wired remote) |
| 41 | 4 / 1 | Indoor room temperature sensor error |
| 42 | 4 / 2 | Indoor coil (pipe) temperature sensor error |
| 44 | 4 / 4 | Human (motion) sensor error |
| 51 | 5 / 1 | Indoor fan motor error |
| 53 | 5 / 3 | Drain pump error: float switch up for 3 minutes |
| 62 | 6 / 2 | Outdoor unit main board error |
| 63 | 6 / 3 | Inverter error |
| 64 | 6 / 4 | Active filter / PFC circuit error |
| 65 | 6 / 5 | IPM error: abnormal current |
| 71 | 7 / 1 | Discharge temperature sensor error |
| 72 | 7 / 2 | Compressor temperature sensor error |
| 73 | 7 / 3 | Outdoor coil (pipe) temperature sensor error |
| 74 | 7 / 4 | Outdoor air temperature sensor error |
| 77 | 7 / 7 | Heat sink temperature sensor error |
| 84 | 8 / 4 | Current sensor error |
| 86 | 8 / 6 | High pressure switch error |
| 94 | 9 / 4 | Overcurrent error |
| 95 | 9 / 5 | Compressor rotor position error: compressor can’t run |
| 97 | 9 / 7 | Outdoor fan motor 1 error |
| 98 | 9 / 8 | Outdoor fan motor 2 error |
| 99 | 9 / 9 | 4-way (reversing) valve error |
| A1 | 10 / 1 | Discharge temperature too high (230°F or more) |
| A3 | 10 / 3 | Compressor temperature too high (226°F or more) |
| A5 | 10 / 5 | Low pressure error |
Not every model uses every code: the list covers Fujitsu’s single-zone and multi-zone ductless range, and codes such as 15, 44 and 53 only apply to units with that feature. Your unit’s model number decides which ones it can show. Multi-zone systems with a branch box add a few more (21, 22, 24, 75, 76, 82, 83 and J2), and some older Fujitsu wired controllers use a different numbering, so check the manual for your model if a code isn’t here.
The Fujitsu mini split error codes homeowners see most
Code 11: indoor and outdoor units can’t communicate
One flash on each lamp is the most common of all Fujitsu mini split error codes. Fujitsu describes it as a serial communication error between the indoor and outdoor units. The first thing to check is whether the outdoor unit has power: a tripped breaker or a switched-off disconnect box beside the outdoor unit produces exactly this code. If it appeared right after installation, it’s usually the connecting cable, and that’s the installer’s job. Our Daikin U4 guide walks through the same kind of fault on another brand.
Codes 41 and 42: indoor temperature sensors
The unit is reading an impossible value from the room sensor (41) or the indoor coil sensor (42). A reset sometimes clears a one-off glitch. If the code returns, the sensor or its connector needs a technician, but it’s one of the cheaper repairs on this list.
Code 51: indoor fan motor
Fujitsu’s guide defines code 51 as the indoor fan running far below the speed it was told to run. Check that the filters aren’t clogged and nothing is blocking the louvers or the fan. If it still happens, the fan motor or the indoor board needs testing.
Codes 62, 63, 64 and 65: outdoor circuit boards
These point to the outdoor unit’s main board, inverter, power-correction circuit or IPM power module. A power surge can trigger them once. Reset the system; if the code returns, it needs a technician, and the repair is usually a board.
Codes 97 and 98: outdoor fan motor
The outdoor fan has slowed below about 100 RPM or stopped. Look for leaves, snow or ice around and inside the fan guard, without reaching in. In winter, our guide to a heat pump blowing cold air in heat mode explains how normal defrost differs from a unit that’s icing up.
Codes 95, A1, A3, A5 and 86: compressor and refrigerant protection
Code 95 means the inverter can’t track the compressor’s position, so the compressor can’t run. A1 and A3 mean the compressor is running too hot, and A5 and 86 are pressure protections. Low refrigerant, a restriction or a failing compressor are all possible causes. None of these are homeowner fixes: reset once, and if the code returns, turn the unit off and call a technician.
What to try before calling a technician
These steps cost nothing and cover the Fujitsu mini split error codes you can actually do something about:
- Write down the flash count on both lamps, and when the error appeared.
- Reset once: turn the unit off, switch off its breaker for about five minutes, then restore power.
- Check the breakers and the outdoor disconnect. If a breaker trips again, leave it off.
- Clean the filters. Fujitsu recommends cleaning the standard air filter every two weeks in normal use.
- Clear the intake and outlet of the indoor unit and anything blocking the outdoor unit.
- If the system is new, call the installer first.
What fixing Fujitsu mini split error codes usually costs
| Repair | Typical cost | Codes it can resolve |
|---|---|---|
| Reset, breaker, filter cleaning | $0 | Temporary codes, 11 from a tripped breaker, 51 |
| Diagnostic visit | $60–$200 | All |
| Fan motor | $200–$700 | 51, 97, 98 |
| Circuit or control board | $150–$700 | 11, 32, 62–65 |
| Refrigerant leak repair | $300–$1,200 | A1, A5 |
| Reversing valve | $200–$650 | 99 |
| Compressor replacement on a mini split | $1,200–$4,500 | 95, A3 if the compressor has failed |
Repair ranges come from Angi’s heat pump repair data and PickHVAC’s mini split cost guide (both May 2026). Check whether your system is still under warranty before paying for a board or compressor, and if you’re facing a compressor on an older system, compare the quote with our heat pump installation cost by state data. Own a different brand? See our Mitsubishi and LG error code lists.
Frequently asked questions
Why is the green light blinking on my Fujitsu mini split?
If only the Operation lamp blinks while heating, the unit is defrosting, which takes up to 15 minutes. If the Operation and Timer lamps blink together while the Economy lamp flashes fast, it’s an error code.
How do I reset Fujitsu mini split error codes?
Turn the unit off, switch off its breaker, wait about five minutes and restore power. If the lamps go back to normal, nothing else is needed.
What does code 11 mean on a Fujitsu mini split?
The indoor and outdoor units can’t communicate. Check that the outdoor unit has power first; if the code returns, the connecting cable or a board needs checking.
Can I keep using my Fujitsu mini split with an error code?
Fujitsu’s advice for a fault indication is to stop the unit and contact service. If a single reset clears it for good, you can keep using it; if it keeps coming back, have it checked.
Seen one of the Fujitsu mini split error codes that isn’t on this list? Tell us and we’ll add it.