How To Troubleshoot and Fix a Mini Split E6 Error Code

By | January 8, 2020

How To Troubleshoot and Fix a Mini Split E6 Error Code
If an E6 error code displays on a mini split there are a few things a DIY type person can do before calling an HVAC tech.

Of course, if in doubt always call a professional.

Below are the steps to troubleshoot and fix an E6 error code.

You will need to know how to use a multi meter for checking voltages and continuity.

What is an E6 error Code on a Mini Split?
An E6 error code is a communication error that the inside unit is not able to communicate with the outside unit.

This includes the high voltage and low voltage lines.

What Causes an E6 Code on a Mini Split?

  • Wiring
  • Open or Bad communication wires
  • Bad high voltage wiring
  • Bad Control Board
  • The most common cause of an E6 error is the communication wires between the inside and outside units.

    This includes the voltage at the outside unit (115/230) and the voltage going to the inside unit.

    Most all mini split units have high voltage going to the outside unit which sends a lower voltage to the inside unit.

    There is also a 4-8 wire communication line between each unit, all of which will need to be checked for a bad connection or an open in a wire.

    If all the wiring and voltages are good the likely problem will be the one of the control boards on the inside or outside units.

    Steps to Troubleshoot and Fix an E6 code
    Voltages will vary between mini split units. A schematic will be on the inside door of both the indoor and outdoor units.

    1. First check the voltage on the outside unit.
    2. Check the voltage on the inside unit.
    3. Check the communication signal wires between the inside and outside units for bad connection or an open wire.
    4. A common method to check the wires for an open is to turn off all power to the system, cross two wires, and check them on the other side for continuity with a meter.
    5. If the voltages are correct and communication line good the problem is most likely a bad control board on the inside or outside unit.

    Above is the basic steps a homeowner can do to fix an E6 error code.

    The problem usually is in the voltage or communication lines.

    Keep in mind bad wiring can damage a control board with both needed to be replaced in some scenarios.

    If all the communication wiring and voltages test good the problems is most likely a bad control board.

    At that point it would be best to call an HVAC tech to fix the unit.



    8 thoughts on “How To Troubleshoot and Fix a Mini Split E6 Error Code

    1. Ruben Oliveras Martinez

      When it rains, does the E-6 code turn on, any ideas?

    2. modou

      can someone please help me i have a problem wit my west point Stan air conditioner 48000btu error e6

      1. Samekia

        is there a way to fix this problem if what was done in the video doesn”t without buying a new board?


      I already checked all the wires between the two units were OK. voltage is OK also .Is there any relation ship with capacitor and the main board .THANK YOU

    4. Walt Vinoski

      This is an incomplete demonstration.
      Where is the details on how to check and measure the communications lines?

      The unit has power, but E6 error does not go away, there should be an electrical schematic with the manual and inside the unit, but it does not have one. My solution is to throw away the unit and purchase a Mitsubishi that is very easy to work on and trouble shoot down to the component level.

      1. Hawkwind212

        Every unit will have different voltages and resistance. They should be in the manual for the unit. Mitsubishi are good units but so are many other brands. Probably best to call a professional.


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