Mitsubishi Electric Mini Split Error Code P9: How to Fix It

Q: What does P9 error code mean on Mitsubishi mini split?

P9 error code indicates the indoor pipe (gas) thermistor is either open circuit or short circuit. This temperature sensor monitors refrigerant gas temperature and is essential for proper system operation.

Q: Can I run my Mitsubishi mini split with P9 error?

No, you should not operate the unit with a P9 error. The system cannot properly control temperature without the gas thermistor, which may lead to poor performance, increased energy consumption, or potential damage to other components.

Q: How much does it cost to fix P9 error on Mitsubishi mini split?

If you replace the thermistor yourself, the part typically costs $15-40. Professional repair usually ranges from $150-300 including labor and parts, depending on accessibility and local service rates.

Q: How do I reset Mitsubishi mini split after fixing P9 error?

After fixing the thermistor issue, turn off the unit and disconnect power for 5 minutes. Restore power and turn the system back on. The error code should automatically clear if the repair was successful.

Q: What causes P9 error code in Mitsubishi mini splits?

P9 errors are typically caused by a failed thermistor sensor, loose wiring connections, corrosion at connection points, physical damage to the sensor, or poor thermal contact between the sensor and the refrigerant pipe.

Abstract

Error code P9 on your Mitsubishi Electric mini split indicates a problem with the indoor pipe (gas) thermistor - it's either open circuit or short circuit. This temperature sensor monitors the refrigerant gas temperature, and when it fails, your system cannot properly regulate cooling or heating.