Mitsubishi Mini Split Error Code UF: How to Fix It

Hard 1-2 hours High Severity Verified June 2026
Summarize with ChatGPTSummarize with ClaudeSummarize with Perplexity Add as Preferred Source on Google
Error Code
UF
Brand
Mitsubishi
Product Type
mini_split
Severity
High
DIY Difficulty
Hard
Estimated Fix Time
1-2 hours
Error code UF on your Mitsubishi mini split indicates a problem with the compressor's power inverter module. This high-severity error means the inverter board is likely failing or has failed, preventing the compressor from running. Attempting DIY repair is possible but requires electrical knowledge and safety precautions.
Ad

Tools You'll Need

How to Fix Error Code UF

  1. Safety First: Power Down the System

    High voltage inside the outdoor unit can cause serious injury or death. Always disconnect power and wait for capacitors to discharge.

  2. Check for Loose Connections

  3. Measure DC Bus Voltage

    Capacitors can hold a dangerous charge. Only perform this step if you are trained in electronics safety.

  4. Inspect for Physical Damage

  5. Test the Compressor Winding Resistance

    Do not wire the compressor back up if readings are abnormal.

  6. Replace the Inverter Board

    Mishandling electrical components can cause system damage or harm. If unsure, call a professional.

  7. Power On and Test

    Do not operate the system with the error code present for extended periods; it may damage the compressor.

Parts You May Need

Inverter board
Check Price on Amazon
Inverter board
Check Price on Amazon
Inverter board
Check Price on Amazon
Inverter board
Check Price on Amazon
Ad

When to Call a Professional

If you are not comfortable working with high-voltage electronics or if the compressor has failed (uneven winding resistance), call a licensed HVAC technician. Inverter board replacement may be covered under warranty – contact Mitsubishi support first.

Frequently Asked Questions

Can I reset the UF code by turning the unit off and on?
A power cycle may temporarily clear the error, but it will return if the underlying inverter issue is not fixed. The code is set because the system detected a fault that prevents safe operation.
Is a failed inverter board covered under warranty?
Most Mitsubishi mini splits have a 5- to 10-year parts warranty. Check your unit's serial number and contact Mitsubishi or your installer. If covered, they will provide a replacement board at no cost.
What tools do I need to diagnose error UF?
You will need a multimeter capable of measuring DC voltage up to 400V, screwdrivers to open the outdoor unit panel, and insulated gloves for safety.
How much does it cost to fix error UF?
If DIY and the inverter board costs $100–$300, total is that plus shipping. Professional repair typically ranges $200–$600 including parts and labor.
Can I run my AC with the UF error code?
No. Running the system with a UF error can damage the compressor. The inverter board is likely not providing proper power, which may cause compressor overheating or failure.

Related Error Codes