Mitsubishi Electric MSZ / MSY / MUZ / MUY GL NA series error code 11 blinks, 2.5 s OFF
Indoor fan motor, or outdoor bus voltage and phase current
Quick answer
On Mitsubishi Electric MSZ / MSY / MUZ / MUY GL NA series, 11 blinks, 2.5 s OFF is a fault. It means indoor fan motor, or outdoor bus voltage and phase current. A first thing to check: Indoor side: a failed indoor fan motor.
- Applies to
- Mitsubishi Electric MSZ / MSY / MUZ / MUY GL NA series
- Mitsubishi Electric MR SLIM GL series split codes · Mini Split
- Type of code
- Fault
- Urgency: Needs attention soon
- First safe check
- Answer the three second hold question, then read the inverter LED: eight is bus-bar voltage, nine is compressor phase current.
What 11 blinks, 2.5 s OFF means on this model
Beep and an immediate blink is the indoor fan motor, where the rotational frequency feedback signal is not emitted for twelve seconds after the fan is operated. A three second hold is the outdoor side, split again by the LED: eight LED blinks means the inverter bus-bar voltage cannot be detected normally, and nine LED blinks means each phase current of the compressor cannot be detected normally.
Symptoms you will notice
- Upper lamp blinks eleven times then pauses 2.5 seconds
- Beep and no hold means the indoor blower is not running or has lost its feedback
- Three second hold and no beep means the system will not start
- The system may start and immediately stop
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:
- Indoor side: a failed indoor fan motor
- Indoor side: a fan that has lost its rotational frequency feedback, often from a failed Hall element or a loose feedback connector
- Indoor side: a seized or obstructed indoor fan wheel
- Outdoor side: a failed inverter P.C. board bus-bar voltage sensing circuit
- Outdoor side: a failed compressor phase current sensing circuit
- Outdoor side: a loose compressor connector or a supply voltage problem
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.
- Answer the three second hold question, then read the inverter LED: eight is bus-bar voltage, nine is compressor phase current.
- On the indoor side, turn the fan wheel by hand and confirm it moves freely, which separates a seized fan from a feedback fault.
- Check the fan motor connector and the compressor connector for loose or corroded pins.
Do not do these
- ×Do not work on the indoor fan circuit if the lamp held steady for three seconds first, because the indoor fan is not involved in that case.
- ×Do not replace the inverter board on the outdoor side before checking the compressor connector and the supply, because both produce the same sensing failure.
- ×Do not reach into the unit or work on connectors with the power switch on.
When to call a technician
Book a technician, do not keep resetting it
This fault will not clear on its own. Every power cycle gives the control one more failed attempt, and repeated attempts are what turn a cheap part replacement into a seized or contaminated system.
- 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.
Turning the fan by hand is reasonable for a homeowner. Fan electronics and board work is a technician job.
What it costs to fix
Parts
Indoor fan motor $150 to $400. Inverter P.C. board $500 to $1,200. Compressor connector $30 to $90.
Labor
Two to four hours once the side and the LED count are established.
DIY or technician
Turning the fan by hand is reasonable for a homeowner. Fan electronics and board 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
- Mitsubishi Electric MR SLIM GL series split codes
- Models in scope
- Mitsubishi Electric MSZ / MSY / MUZ / MUY GL NA series
- 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.