Fujitsu Mini-Split Error Code 00: How to Fix It

Medium 30-60 minutes Medium Severity Verified June 2026
Error Code
00
Brand
Fujitsu
Product Type
mini_split
Severity
Medium
DIY Difficulty
Medium
Estimated Fix Time
30-60 minutes
Error code 00 on a Fujitsu mini-split indicates a serial communication error between the indoor and outdoor units. This often happens due to loose wiring, a faulty control board, or electrical interference. Here’s how to troubleshoot and fix it.
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Tools You'll Need

How to Fix Error Code 00

  1. Power Down the System

    Always power off completely before working on electrical connections to avoid shock.
  2. Inspect Wiring Connections

  3. Check for Wiring Polarity

  4. Measure Voltage on Communication Wires

    Only perform this step if comfortable with live voltage testing. Otherwise, call a professional.
  5. Test for Short or Open Circuit

  6. Inspect Control Boards

  7. Reset the System (If No Hardware Issues)

Parts You May Need

Fujitsu indoor or outdoor control board
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Communication wire (shielded twisted pair)
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Fujitsu indoor or outdoor control board
Check Price on Amazon
Communication wire (shielded twisted pair)
Check Price on Amazon
Fujitsu indoor or outdoor control board
Check Price on Amazon
Communication wire (shielded twisted pair)
Check Price on Amazon
Fujitsu indoor or outdoor control board
Check Price on Amazon
Communication wire (shielded twisted pair)
Check Price on Amazon
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When to Call a Professional

If you are not comfortable working with high voltage, or if after checking all wiring and boards the error persists, call an HVAC technician. Replacing a control board requires precise handling and may void warranty if not done professionally.

Frequently Asked Questions

What does error code 00 mean on a Fujitsu mini-split?
Error 00 indicates a serial communication error between the indoor and outdoor units. The system cannot exchange data properly, often due to wiring issues or faulty control boards.
Can I fix Fujitsu mini-split error 00 myself?
Yes, if you have basic electrical skills. Check and tighten wiring connections, verify polarity, and reset the system. Often these steps resolve the error. For board replacements, call a pro.
How do I reset a Fujitsu mini-split error code 00?
Turn off the power to both units at the breaker for at least 30 minutes. Then turn it back on. If the error returns, there is a hardware issue.
What tools do I need to diagnose Fujitsu error 00?
A multimeter, screwdrivers, wire strippers, and a voltage tester. A multimeter is essential for checking voltage and continuity.
How much does it cost to fix error 00 on a Fujitsu mini-split?
DIY costs are for tools (multimeter ~$20-50). Hiring a technician typically costs $100-300 for diagnosis plus parts. Control board replacement can be $150-400.