Mitsubishi Mini-Split Error Code P8: How to Fix It
Medium 45 minutes to 1.5 hours Medium Severity
Verified June 2026
- Error Code
- P8
- Brand
- Mitsubishi
- Product Type
- mini_split
- Severity
- Medium
- DIY Difficulty
- Medium
- Estimated Fix Time
- 45 minutes to 1.5 hours
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Tools You'll Need
- Multimeter
- Screwdrivers (Phillips and flathead)
- Garden hose or coil cleaner spray
- Safety gloves and goggles
How to Fix Error Code P8
-
Turn Off Power to the Unit
Always shut off power before working on the unit to avoid electric shock. -
Clean the Outdoor Coils
Avoid using high-pressure washers, as they can damage the fins. -
Inspect the Outdoor Coil Thermistor
Handle the thermistor carefully; it is sensitive and can be damaged easily. -
Check for Refrigerant Leaks
Refrigerant handling requires EPA certification and proper equipment. -
Reset the System
Parts You May Need
Outdoor coil thermistor (temperature sensor)
Check Price on Amazon
Outdoor coil thermistor (temperature sensor)
Check Price on Amazon
Outdoor coil thermistor (temperature sensor)
Check Price on Amazon
Outdoor coil thermistor (temperature sensor)
Check Price on Amazon
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When to Call a Professional
If cleaning the coils and checking the thermistor doesn't resolve the error, or if you suspect a refrigerant leak or control board failure, call a qualified HVAC technician. Refrigerant leaks require professional repair and EPA certification.Frequently Asked Questions
Can I run my Mitsubishi mini-split with error code P8?
It's not recommended. The system may shut down to protect the compressor. Continuing to run it could cause further damage.
How much does it cost to fix error P8?
If it's a dirty coil, cleaning is free. Replacing a thermistor costs $20-$50 for the part plus labor if hired. Refrigerant repairs range from $200-$800+.
What does 'outdoor coil temperature abnormal' mean?
The outdoor coil sensor has detected a temperature outside normal operating range, which could be due to a dirty coil, fan failure, sensor fault, or refrigerant issue.
How do I test the outdoor coil thermistor?
Disconnect the thermistor from the control board. Use a multimeter on the resistance setting. At room temperature (77°F), it should read around 10kΩ. Check your unit's service manual for exact values.
Can a dirty air filter cause error P8?
No, a dirty indoor filter does not directly trigger outdoor coil temperature errors, but poor airflow can affect overall system performance. Clean both indoor and outdoor filters regularly.