Fujitsu ASTG09 / ASTG12 / AOTG09 / AOTG12 KMTC error code 35
Manual auto switch error
Quick answer
On Fujitsu ASTG09 / ASTG12 / AOTG09 / AOTG12 KMTC, 35 is a fault. It means manual auto switch error. A first thing to check: The manual auto switch left in a position between manual and auto.
- 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: Book a technician
- First safe check
- Check the physical position of the manual auto switch and confirm it is fully in one position rather than between the two.
What 35 means on this model
The manual and auto switch on the unit is in an invalid or unexpected position, so the unit cannot tell whether it is being controlled locally or automatically and has stopped. This is a physical switch position fault rather than an electronic one, which makes it one of the cheaper codes on the platform, but it will keep coming back until the switch is put where the unit expects it.
Symptoms you will notice
- Code 35 on the controller or the indicator lamps
- The unit will not start or change mode
- The unit does not respond to the controller as expected
- The fault appears after a service, a unit move, or reassembly
- The manual auto switch is loose or has been left part way
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:
- The manual auto switch left in a position between manual and auto
- A switch that has been damaged or is mechanically loose
- A wiring fault at the manual auto switch
- A unit that has been reassembled with the switch incorrectly set
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 physical position of the manual auto switch and confirm it is fully in one position rather than between the two.
- Check the switch itself for looseness or damage, since a switch that no longer detents can sit in an unreadable position.
Do not do these
- ×Do not spray a lubricant or contact cleaner into the switch expecting it to fix a position fault. The switch needs to be seated properly, not cleaned.
- ×Do not work on the switch wiring with the power switch on.
When to call a technician
Worth scheduling, and worth your own checks first
You can usually keep living with this for a short while, but it will not fix itself. Do the safe checks below first, because a tripped switch or a blocked airflow is a five-minute fix that would otherwise cost you a service call.
- 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.
Checking and setting a physical switch is reasonable for a confident homeowner. Wiring work is a technician job.
What it costs to fix
Parts
Manual auto switch $20 to $70. Indoor main PCB $250 to $550 if the switch is integral.
Labor
One to two hours to locate and correct.
DIY or technician
Checking and setting a physical switch is reasonable for a confident homeowner. Wiring work is 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
- Models in scope
- Fujitsu ASTG09 / ASTG12 / AOTG09 / AOTG12 KMTC
- 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.