2 Green Lights On Mitsubishi Mini Split Problem & Solution.

You can agree that Mitsubishi air conditioners are intelligent because they indicate when something is amiss. You, however, have to match their intelligence and interpret the lights, and the commonest are 2 green lights on Mitsubishi mini split.

Static 2 lights on a Mitsubishi mini split often indicate the heat pump is yet to reach its preset temperature, but it’s working to heat and cool your space. Blinking green lights may suggest an overvoltage, but if accompanied by an error code, it indicates a fault.  

Speaking of faults, you may have to consider the possibility of poor airflow, frozen coil, low refrigerant, malfunctioning thermistor, electrical fault, or poor installation.

So, not every time you see the green lights point to a problem with your air conditioning system. An issue like an over-voltage, where the lights blink, is likely to culminate with your air conditioning system shutting down and restarting. In that case, you don’t have to do anything.

You also don’t have to lift a finger if the issue is the heat pump indicating that it’s yet to reach its preset temperature. The concern should be when the indicator lights are accompanied by a code, as that means something is wrong, which you should fix.   

I’ll explain all these eight reasons and what to do in each case. Here’s a table overview you can use to troubleshoot your mini split.

2 green lights on Mitsubishi mini split

Quick 2 Green Lights On Mitsubishi Mini Split Troubleshooting Guide

Most Likely ReasonWhat to Do
(Static 2 Green Lights)
1.The heat pump is yet to reach the preset temperatureJust wait for the heat pump to get to its preset temperature.
(Blinking Green Lights) 
2.Overvoltage (mini-split likely to shelf shut)Wait for the air conditioning system to self-shut and restart
(Green Lights with Error Code) 
3.Poor airflow Improve airflow by cleaning the air filter, vents, and coils
4.Frozen coil Thaw out the evaporator coil if it’s frosty
5.Low refrigerant Ask an expert’s help to determine and fix the source of the coolant leakage
6.Malfunctioning thermistor Replace the thermistor if it looks faulty or lacks continuity
7.Electrical fault Reset the breaker if it tripped and leave any other electrical issue to an expert technician/electrician
8.Poor AC installationHave an expert check the system’s installation

What Does 2 Green Lights Mean On Mitsubishi Mini Split?

Generally, a Mitsubishi mini split heat pump has two light indicators on its bottom right end. These indicator lights tell you the status of the heat pump and when something is wrong. 

If only one static green light is illuminating, the heat pump is close to reaching its pre-programmed temperature (no more than 20C). That, however, is not stopping the heat pump from cooling or heating your space.

But once the two green lights illuminate, it shows the heat pump is not near its preset temperature, perhaps by more than 20C. 

But like in the first case, the heat pump will cool and heat your space until it reaches the target temperature where the light will go off.

Note, however, that sometimes the green lights may not be static but may blink continuously, and at other times, they are accompanied by the error code P6 or any other. 

In the first case, the issue could be an overvoltage, and in the second case, the cause could be a detected fault. Let me talk about these potential causes next.

How to Troubleshoot 2 Green Lights on Your Mitsubishi Mini Split

You should identify if the green lights are static, continually blinking, or accompanied by an error code. That’ll help you fix it accordingly.

Here are the eight issues you should know about and what to do in each case.

1.  Heat Pump Yet to Reach its Preset Temperature (Static Green Lights)

As shared earlier, if the green lights are barely blinking, it often indicates that the heat pump has yet to reach its pre-programmed temperature. That, however, doesn’t stop it from warming or cooling your space.


Since the lights don’t indicate anything alarming, you don’t have to do anything. Just wait for the heat pump to reach the preset temperature, and the lights will go off. If they don’t, then consider the other possibilities.

what does 2 green lights mean on Mitsubishi mini split

2. Overvoltage (2 Green Lights On Mitsubishi Mini Split Blinking)

Sometimes the green lights may constantly blink. If so, the air conditioner likely detected a power spike and is planning to go into a shelf shut mode.

Not only does the self-shutdown protect the air conditioning system, but it also warns you of its imminent shutdown.


Since the indicator lights indicate an imminent shutdown, there’s nothing to do here unless the issue is not an overvoltage. If the system shelf shuts down, it’ll restart itself. So, wait to see.

Blinking Green Light On Mitsubishi Mini Split Accompanied by An Error Code

3. Poor Airflow 

Too much debris or dirt will clog the air filter vent and coils and interfere with the cooling. If the unit doesn’t cool properly, it’s likely to flash some lights.  


Carefully check the air filter, vents, and coils for dirt and debris clogging and clean them. That’ll improve the cooling and possibly stop the blinking if poor airflow is the culprit.

4. Frozen or Faulty Evaporator Coil

In most cases, the error code P6 pops up when something is wrong with the unit’s evaporator coils. The error code could suggest that the evaporator coil is frozen, so you should inspect it. 

But at times, the evaporator coil could malfunction not because it’s frozen but because of a malfunctioning thermostat (discussed below).


Inspect the evaporator coil for frostiness and thaw it out. 

5. Low Refrigerant 

Your Mitsubishi mini split will sometimes flash the green lights because it’s not cooling well. That often happens when the coolant/refrigerant level drops, especially in the compressor. 

Once that’s the case, you should identify the cause of the coolant leakage and fix it. 


Watch out for odd smells and droppings, as they likely suggest a refrigerant leakage. If so, ask for an expert’s help to fix the leakage.

6. Malfunctioning Thermistor 

A malfunctioning thermistor directly impacts the evaporator coil performance, and once the evaporator coil malfunctions, the mini split will recognize that. 

Overall, you can tell a malfunctioning thermostat if it shows burned marks or has frayed wires. 


Inspect the thermistor for burns and failed wires and replace it if that’s the case. If you are handy, you can even test it for continuity (using a multimeter). If it has no continuity, replace it. 

Mitsubishi Mr slim troubleshooting blinking light

7. Electrical Fault

An electrical fault, especially a writing issue, can cause the blinking green lights and an error code. Sometimes the mini split will do so when there’s a power outage, the breaker trips, or any other electrical fault.


Check the breaker box and reset the breaker if it’s tripped. But if you suspect a wiring issue or electrical malfunction, talk to an expert technician.

8. Poor AC Installation 

If your mini split is a new installation that was wrongly done, the unit may indicate that by flashing green lights. That means something needs fixing, and you need an expert to fix it. 


Call a mini split expert or Mitsubishi dealer if you suspect the AC installation to be wrong.

Mitsubishi Mini Split Blinking Codes

Let’s now talk about the blinking codes in general and their interpretation. Note that not only should you note the color of the blinking light by your mini split but also the number of times it blinks.

Here are the most everyday blinking codes, their interpretation, and fixes.

Number of blinking timesInterpretationFix
2Wire break or heat exchange sensor faultContact an HVAC expert for assistance 
5Overheated compressor (due to a low refrigerant or overworking)Contact an HVAC expert for help
6Communication error due to a broken wire power failure or faulty circuit boardCall an expert technician to fix the issue
7Fan motor faultReplace the outdoor motor fan or circuit board
14Burnt or failed power module (electronic control board)First, check the wiring, and if they are okay, replace the module

Mitsubishi Mr Slim Troubleshooting Blinking Light

Mitsubishi Mr. Slim is no different from Mini slim. It also warns you through its indicator light when something is wrong. (Valium) As far as the blinking of flashing indicator lights go, you should interpret the flashes alongside the accompanying codes.

That brings us to the following combinations:

a) 2 Green Flashes + 5 Red Flashes + Controller 6600

If your Mr. Slim flashes its green LED twice and its red LED five times and displays the code controller 6600, that shows an address confusion. To fix it,  reset your Mitsubishi unit, which you can do by quickly unplugging or turning off the isolator/breaker switch. 

b) 2 Green Flashes + 5 Red Flashes + Controller 6602

If your unit displays the code controller 6602 instead of 6600 and flashes the green LED twice and the red LED five times, it indicates a hardware malfunction or a communication wiring fault. So, you need an expert to check the AC system out and fix it.  

c) 2 Green Flashes + 5 Red Flashes + Controller 6606

The mini slim flashes the green light twice and the red LED five times and display the code ‘controller 6606’ to show failed communication involving the processor.

It could be that multiple systems are interconnected but not working in harmony. You’ll also need an expert technician to check and fix the issue. 

d) 2 Green Flashes + 3 Red Flashes

Lastly, if two green and 3 LEDs flash, the unit is not responding to the remote control. It doesn’t mean that the remote control is faulty, but it’s often a wiring or voltage issue touching on the mini split. An expert can help you fix it.

Mitsubishi mini split blinking codes

People Also Ask

1.  What Are The Two Green Lights On My Mitsubishi Mini Split?

The two green lights on Mitsubishi mini split often indicate that the heat pump is yet to reach the preset temperature but is working to keep your space warm or cool. But if there’s an error code, the warning could indicate a fault.

2. How Can I Reset My Mitsubishi Mini Split?

You can reset a Mitsubishi mini split by pressing the ‘reset’ button on its bottom side. Alternatively, you can turn its isolator switch or briefly unplug it.

3. Why Is My Heat Pump’s Green Light Blinking?

If your heat pump blinks green slowly, the furnace is not hot enough despite being hot. But if the pump continuously blinks after resetting the unit, the circuit board is likely imperfect, which you should replace. 

Closing Thought On 2 Green Lights On Mitsubishi Mini Split

Now you know what the two green lights on your Mitsubishi mini split mean. It, however, does not mean that you should panic, as in most cases, the lights are not alarming. You should only worry when they perpetually blink or are accompanied by an error code.