Mitsubishi Electric MSZ / MSY / MUZ / MUY GL NA series error code 2 blinks, 2.5 s OFF
Indoor coil thermistor, or outdoor power system
Which models this applies to. This page covers the Mitsubishi Electric MR SLIM GL series split codes.
What is specific to the MSZ / MSY / MUZ / MUY GL NA series platform
MSZ and MSY indoor units with MUZ cooling only and MUY heating outdoor units on R410A. There is no numeric display: you count blinks of the upper operation indicator lamp on the indoor unit. The same blink count can mean an indoor fault or an outdoor one, and a three second steady hold before the blinking with no beep is what tells the two apart, with a second LED inside the outdoor unit narrowing several outdoor codes to one part.
Your control board does not print the code. It blinks an LED, and you count the flashes against a legend printed on the board or inside the access panel. Count a full cycle before you read it, because the pattern pauses and repeats.
Quick answer
On Mitsubishi Electric MSZ / MSY / MUZ / MUY GL NA series, 2 blinks, 2.5 s OFF is a fault. It means indoor coil thermistor, or outdoor power system. A first thing to check: Indoor side: a failed indoor coil thermistor, or a short or open in its wiring.
- 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
- Establish the three second hold question first, exactly as with one blink, because the two sides have nothing in common.
What 2 blinks, 2.5 s OFF means on this model
Beep and an immediate blink means the indoor coil thermistor is short or open circuit, detected every eight seconds during operation. A three second hold first means the outdoor overcurrent protection cut-out has operated three consecutive times within one minute after the compressor started, and the manual directs reconnecting the compressor connector and checking the stop valve.
Symptoms you will notice
- Upper lamp blinks twice then pauses 2.5 seconds
- Beep and no three second hold means the indoor unit will not heat or cool
- Three second hold and no beep means the system will not start, and it may reset and try again
- The system may restart after a delay and then trip again
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 coil thermistor, or a short or open in its wiring
- Outdoor side: an overcurrent cut-out tripping three times in a minute after start
- Outdoor side: a compressor connector that is loose or not seated
- Outdoor side: a supply voltage problem
- Outdoor side: a closed stop valve forcing the compressor to work against a restriction
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.
- Establish the three second hold question first, exactly as with one blink, because the two sides have nothing in common.
- If it is the outdoor side, reconnect the compressor connector and check the stop valve, which is the order the manual gives.
- Check the supply voltage at the outdoor unit, because an overcurrent cut-out tripping three times in a row is often a voltage symptom rather than a compressor one.
Do not do these
- ×Do not work on the indoor coil thermistor when the lamp held steady for three seconds first.
- ×Do not keep restarting the system on the outdoor power fault. Three consecutive overcurrent cut-outs in a minute is the drive protecting itself, and repeated restarts damage the drive.
- ×Do not open a stop valve or work on the refrigerant circuit without recovery equipment and the factory procedures.
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.
A technician job either way, because the outdoor side involves the compressor connector and the supply.
What it costs to fix
Parts
Indoor coil thermistor $25 to $80. Compressor connector terminals $15 to $50. Stop valve $30 to $90.
Labor
Two to four hours if the fault is at the outdoor unit.
DIY or technician
A technician job either way, because the outdoor side involves the compressor connector and the supply.
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
- How this model reports the code
- Blinking LED, counted against a legend
- Models in scope
- Mitsubishi Electric MSZ / MSY / MUZ / MUY GL NA series
- How this platform differs
- MSZ and MSY indoor units with MUZ cooling only and MUY heating outdoor units on R410A. There is no numeric display: you count blinks of the upper operation indicator lamp on the indoor unit. The same blink count can mean an indoor fault or an outdoor one, and a three second steady hold before the blinking with no beep is what tells the two apart, with a second LED inside the outdoor unit narrowing several outdoor codes to one part.
- 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.