Fujitsu ASTG09 / ASTG12 / AOTG09 / AOTG12 KMTC error code 44
Human sensor error
Which models this applies to. This page covers the Fujitsu GENERAL AIRSTAGE KMTC wall split codes, indoor and outdoor.
What is specific to the ASTG09 / ASTG12 / AOTG09 / AOTG12 KMTC platform
ASTG09KMTC and ASTG12KMTC indoor units with AOTG09KMTC and AOTG12KMTC outdoor units on R32. A compatible non-polar wired controller shows the code directly on its display. The supplied wireless controller has no screen and shows the same codes as a flashing pattern on the indoor indicator lamps instead. The service reference gives a separate main PCB, control unit and inverter assembly identification for each of the two capacities, so a board from the wrong capacity is a recognised cause of codes 32 and 62.
Your control board prints the code as text, for example F01 or EE3, so you read it off the display rather than counting blinks. The printed number is the fault itself, not a position in a table.
Quick answer
On Fujitsu ASTG09 / ASTG12 / AOTG09 / AOTG12 KMTC, 44 is a fault. It means human sensor error. A first thing to check: A failed human presence sensor.
- Applies to
- Fujitsu ASTG09 / ASTG12 / AOTG09 / AOTG12 KMTC
- Fujitsu GENERAL AIRSTAGE KMTC wall split codes, indoor and outdoor · Mini Split
- Type of code
- Fault
- Urgency: Worth keeping an eye on
- First safe check
- Check the sensor lens for dust or film, because a dirty lens on a presence sensor produces a fault that looks like a dead sensor.
What 44 means on this model
The optional human presence sensor has reported a fault, so the unit has lost the occupancy sensing that lets it respond to an empty room. The service reference lists the optional interfaces for this series as the wired remote controllers, the communication kit, the external input and output PCB, the external connect kit and the wireless LAN adapter, and the human sensor is not among them, so treat the sensor as an add on on the unit you own rather than standard on the range. The practical effect is comfort and running hours rather than a broken machine.
Symptoms you will notice
- Code 44 and the unit still heats and cools
- The unit no longer responds to whether the room is occupied
- The unit runs all day in an empty room
- The fault appeared after a sensor was fitted or moved
Common causes
The code tells you what the control detected, not which part failed. These are the causes we see most often, roughly in order of likelihood:
- A failed human presence sensor
- A wiring or connector fault at the sensor
- A failed indoor main PCB input for the sensor
- A dirty or obstructed sensor lens
- A sensor installed where it cannot see the room
What you can safely check
These are homeowner-level checks. None of them need you to open a live electrical compartment or work on gas.
- Check the sensor lens for dust or film, because a dirty lens on a presence sensor produces a fault that looks like a dead sensor.
- Check the connector and the wiring back to the indoor unit.
- Confirm the sensor can actually see the occupied part of the room from where it is fitted.
Do not do these
- ×Do not replace the indoor main PCB for a 44 before ruling out the sensor and its wiring.
- ×Do not cover the sensor to stop the unit running. Losing occupancy sensing is a feature loss, not a repair.
When to call a technician
No call needed yet, but write it down
Note the date and the exact code, and watch whether it comes back. If it turns into a repeat fault or starts affecting performance, that is when it becomes worth a technician.
- The refrigerant circuit is sealed and legally requires licensed handling. Opening it without certification releases refrigerant and can put the whole system in violation of regulation, so a low-pressure or high-pressure fault on this equipment is a call-out, not a weekend job.
- If the appliance has stopped mid-cycle, is making a noise you have not heard before, or smells burnt, stop reading here and call. Those are symptoms of something the fault code does not describe well enough.
A technician job.
What it costs to fix
Parts
Human sensor $80 to $220. Indoor main PCB $250 to $550.
Labor
One to two hours to diagnose and replace.
DIY or technician
A technician job.
Typical US part and labor ranges, 2026. They vary by region, model and contractor, so treat them as a planning figure, not a quote.
Scope of this code
- Code table
- Fujitsu GENERAL AIRSTAGE KMTC wall split codes, indoor and outdoor
- How this model reports the code
- Printed on the control display
- Models in scope
- Fujitsu ASTG09 / ASTG12 / AOTG09 / AOTG12 KMTC
- How this platform differs
- ASTG09KMTC and ASTG12KMTC indoor units with AOTG09KMTC and AOTG12KMTC outdoor units on R32. A compatible non-polar wired controller shows the code directly on its display. The supplied wireless controller has no screen and shows the same codes as a flashing pattern on the indoor indicator lamps instead. The service reference gives a separate main PCB, control unit and inverter assembly identification for each of the two capacities, so a board from the wrong capacity is a recognised cause of codes 32 and 62.
- Checked
- Confirm on your own unit
- Find the model number on the data plate, then check this code in the service manual for that model. Manufacturers revise code tables between model years, and a revised board can renumber a fault.