Updated On

April 16, 2024

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    Do you see an ‘E4’ error code on your portable or mini split air conditioner? If so, you are in the right place.

    In this guide, we will tell you how to troubleshoot an E4 error code and answer questions like:

    • What should you do if your air conditioner displays an error code?
    • Is it dangerous to use your air conditioning if it shows an error code?
    • Do you need to maintain your portable air conditioner or mini-split?
    • How can you properly maintain your air conditioner to avoid malfunctions?

    AC error codes are concerning, but most are easy to address with the tips below. So, let’s get into it.

    What Is An E4 Error Code?

    Technically, the E4 error is not an error at all. It actually tells you, your unit is going into defrost mode. That does, however, mean that something has caused your unit to get too cold. A broken temperature sensor can also cause your AC to enter defrost mode. 

    What Causes An AC To Go Into Defrost Mode?

    There are many reasons your air conditioner may go into defrost mode. Here are the most common causes. 

    • Low freon 
    • A broken heat pump
    • High pressure or low pressure 
    • It is too cold to run your AC
    • There is a broken outdoor ambient temperature sensor or indoor temperature sensor

    You would think all manufacturers would use the same codes to make it easier for repair contractors and consumers, but that is not the case. So, the above are troubleshooting tips you can use on any unit. You can also find a qualified HVAC technician to solve the problem for you.

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    Do Air Conditioner Error Codes Differ By Manufacturer Or Type?

    However, for the most part, the E4 error code means that the unit is entering defrost mode. You will hear a difference in the fan speed when your unit changes.

    When the fan motor slows, it sounds like the unit performs as an air purifier or dehumidifier. It basically just passes air over the unit without cooling it. 

    What Do Other Error Codes Mean? 

    It helps to have a reference for some of the most common error codes. So, here is a list of some that you may encounter. Print it out or bookmark this page, so you do not have to search Google the next time you have a question about AC error codes. 

    F1, F2, And F3 Error Codes

    If you see any number proceeded by an ‘F,’ it is not an error code. It is simply telling you that the unit is in fan mode. The number following tells you what speed it is on.

    E Error Codes 

    Each E error code means something different. Some signify an issue with a specific component, while others tell you that the unit changed modes. 

    E1 Error Code – There is a room temperature malfunction.

    E2 Error Code – A short in the indoor pipe sensor

    E3 Error Code – An indoor fan speed problem likely attributed to a malfunctioning indoor circuit board or indoor fan motor. 

    E5 Error Code – The water collection plate is full

    E6 Error Code – A disconnect between the indoor and outdoor units possibly caused by low voltage or an open circuit. 

    E7 Error Code – The indoor and outdoor units are not working in sync. 

    E8 Error Code – Occurs sometimes in high heat or humidity. 

    E9 Error Code – A loose connection on the outside unit. 

    Keep in mind, manufacturers use different codes, and there are error codes for discharge temperature, room-temperature sensor, inverter, PCB, and other malfunctions. These codes may not indicate your specific issue. 

    It is always best to check your manual, but these are a good place to start if you do not have access to it. 

    For more information on error codes and how to resolve them, check out this video:

    A Final Thought On Now To Fix An E4 Error Code On Your Air Conditioner

    It does not matter if you are operating a portable air conditioner, mini-split, or central HVAC. Your system is complex. Many components depend on each other. 

    If one is not working properly, the unit can quickly freeze. Older systems that lack current technology could freeze over and cause a lot of damage.

    Ice can form on your indoor or outdoor unit, on the AC lines, and in the ducts. The E4 error code does not signify what is causing the unit to freeze or get too cold to operate without causing damage. 

    Air conditioners usually break on the hottest days because they have to work hardest to maintain a comfortable ambient temperature. Do not get caught off guard on a day when you need your AC the most. Choose one of our top recommended HVAC companies to help you out.

    Editorial Contributors
    avatar for Alexis Bennett

    Alexis Bennett

    Contributor

    Alexis is a freelance writer with nearly a decade of experience covering the home services industry. She’s built considerable expertise in roofing, plumbing, and HVAC, as well as general construction and real estate matters. In her free time, Alexis enjoys coaching women’s golf. She lives in the Triad area of North Carolina.

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    photo of Andrew Dunn

    Andrew Dunn

    Senior Editor

    Andrew Dunn is a veteran journalist with more than 15 years of experience reporting and editing for local and national publications, including The Charlotte Observer and Business North Carolina magazine. His work has been recognized numerous times by the N.C. Press Association and the Society of American Business Editors and Writers. He is also a former general contractor with experience with cabinetry, finish carpentry and general home improvement and repair. Andrew earned a degree in journalism from the University of North Carolina at Chapel Hill, as well as a certificate in business journalism. He lives in Charlotte, N.C.

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