Daikin Mini Split Error Code C6: How to Fix It

Medium 30-45 minutes Medium Severity Verified June 2026
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Error Code
C6
Brand
Daikin
Product Type
mini_split
Severity
Medium
DIY Difficulty
Medium
Estimated Fix Time
30-45 minutes
Error code C6 on your Daikin mini split indicates a short circuit in the coil thermistor (R4T). This sensor monitors the temperature of the indoor coil, and a short can cause the system to stop cooling or heating. Follow these steps to diagnose and fix the issue.
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Tools You'll Need

How to Fix Error Code C6

  1. Turn Off Power and Access the Indoor Unit

    Ensure power is completely disconnected before proceeding to avoid electric shock.

  2. Locate the Coil Thermistor (R4T)

  3. Disconnect and Test the Thermistor

    Handle the multimeter leads carefully to avoid shorting the pins.

  4. Check Wiring and Connectors

  5. Replace the Faulty Thermistor

    Ensure the replacement thermistor matches the original resistance curve (typically 10kΩ at 25°C).

  6. Reassemble and Test

Parts You May Need

Daikin coil thermistor (R4T replacement)
Check Price on Amazon
Wire connectors or crimp terminals
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Daikin coil thermistor (R4T replacement)
Check Price on Amazon
Wire connectors or crimp terminals
Check Price on Amazon
Daikin coil thermistor (R4T replacement)
Check Price on Amazon
Wire connectors or crimp terminals
Check Price on Amazon
Daikin coil thermistor (R4T replacement)
Check Price on Amazon
Wire connectors or crimp terminals
Check Price on Amazon
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When to Call a Professional

If the thermistor tests fine (correct resistance) and wiring is good, the control board might be faulty. Replacing the board requires advanced electrical knowledge and should be done by a certified HVAC technician. Also, if you're uncomfortable working with electronics or exposing coil tubing, call a professional.

Frequently Asked Questions

Can I bypass the coil thermistor temporarily?
No, bypassing the thermistor can cause the system to run dangerously or not operate at all. It must be replaced with a correct thermistor.
What causes the coil thermistor to short?
Moisture, corrosion, physical damage, or age-related wear can cause a short circuit in the thermistor.
How much does a replacement coil thermistor cost?
A generic Daikin coil thermistor costs between $10 and $30. Always verify compatibility with your unit model.
Can I clean the thermistor instead of replacing it?
Cleaning won't fix a short circuit. If it's shorted, replacement is necessary. You can gently clean the exterior with a dry cloth, but internal damage requires replacement.
Will error code C6 clear automatically after fixing?
Yes, once the short is resolved and power is cycled, the error code should clear. If it doesn't, there may be another issue.

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