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Mitsubishi Mini-Split Troubleshoot: Error Codes Guide

One blinking light or weird code doesn’t mean disaster, just a signal to act.

If you’ve ever wondered what those flashing letters or numbers on your Mitsubishi mini split mean; or asked “how to fix my Mitsubishi mini split” when something goes wrong; you’re in the right place. 

This guide gives you Mitsubishi mini split troubleshooting help that’s clear, useful, and to the point.

What Are Mitsubishi Mini-Split Error Codes

Mitsubishi mini split error codes are diagnostic messages your indoor or outdoor mini split unit shows when something in your mini split isn’t right. They appear as letters/numbers (e.g. E0, P6, etc) or via LEDs. They help you figure out what part of the mini split system is off.

These codes do not tell you how to fix things in every case. They point you in a direction. Use them. Don’t fear them.

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Common Mitsubishi Mini-Split Error Codes & What They Mean

Here are many of the most frequent error codes, what likely is wrong, and what you might check. Always refer to the model-specific manual for exact definitions.

Error Code

What It Means

Possible Cause / What You Can Do

P1

Intake air sensor error

 

Sensor of the mini split might be dirty, failing, or its wiring loose.

P2-P9

Pipe thermistor / liquid pipe sensor error

 

Wiring or sensor of the mini split damaged; sensor might be disconnected.

E0

Communication error between indoor and outdoor unit of the Mitsubishi mini split

 

Check wiring, check connections of the mini split, reset power of your cooling appliance. 

E6-E7

Indoor/outdoor communication error

 

Again wiring, electrical issues, perhaps mini split circuit board if serious. 

P4

Drain sensor error

 

Drainage path of the mini split may be blocked; sensor may be wet or damaged. 

P5

Drain pump error

 

Pump may be stuck; check for blockages or failed pump. 

P6

Freezing or overheating safeguard activation

 

Outdoor coils dirty; airflow poor; refrigerant issues. 

PA

Forced compressor shutdown or compressor over-load

 

Electrical issue; compressor of the mini split may be taxed; sometimes overheat. 

E1/E2

Remote control or control board error

 

Possibly remote broken; control board needs inspection. 

U3-U4

Outdoor thermistor open or short

 

Sensor itself or wiring issue. 

UP / UF

Compressor overcurrent or locked compressor condition

 

Electrical fault; mini split compressor could need repair by a technician. 


Mitsubishi Mini-Split Troubleshooting Tips

These are safe steps you can try at home to resolve many error codes. If nothing works, call a professional.

  1. Turn Off & Reset Power

Switch off power to your Mitusibishi mini split. Wait 5-10 minutes. Then turn it back on. Many E-codes or communication errors can clear after reset.

  1. Check Filters & Airflow

Dirty filters of your mini split reduce airflow; blocked intake or vents strain the Mitsubishi mini split, cause P6 or P5-type codes. Clean filters monthly. Keep outdoor Mitsubishi mini split clear of leaves, debris.

  1. Inspect Wiring & Sensors

Loose connections or damaged wires in your mini splits often trigger E0, U3-U4 or sensor-related error codes. Look for loose screws, exposed wires.

  1. Check Drain Pump

If P4 or P5 shows up or water is leaking, inspect drain hose or pan. Clean clogs. Make sure your mini split drain pump works.

  1. Watch Outdoor Conditions

If outdoor coil is blocked, or mini split unit is overheating, or frost builds up, cleaning coils of the mini split helps. Also avoid blocking airflow around outdoor Mitsubishi mini split.

  1. When Refrigerant Might Be the Issue

If error codes suggest high/low pressure or compressor problems (like PA, P6, etc), then refrigerant level may be low or there may be a leak. Only certified HVAC techs should handle refrigerant.

Mitsubishi Mini-Split Maintenance Tips

Good maintenance prevents many error codes and keeps your Mitsubishi mini split lasting longer.

  • Clean or wash air filters of your mini split every month. More often if pets or dusty environment.

  • Clean outdoor Mitsubishi mini split coil and fins at least twice a year. Avoid plants or debris around it.

  • Inspect drain lines, drain pans yearly. Keep them clear so water flows freely.

  • Have sensors and wiring of your mini split checked annually. Loose connections often cause hidden faults.

  • Schedule professional check-ups yearly. Tech can test refrigerant, electrical connections, compressor.

These help reduce Mitsubishi mini split maintenance tips and lessen surprises.

When You Need a Technician

Some error codes or symptoms should never be ignored.

  • Mini split compressor doesn’t start or shows locked condition: serious issue.

  • Refrigerant leak risk or pressure fault in your mini split.

  • Repeated error codes that reset but reappear quickly.

  • Burning smells or visible electrical sparks.

  • Control board failure.

Calling someone certified avoids damage to your mini split and keeps warranty intact.

Klima - Smart Home Thermostat for Mini-splits, Air Conditioners and Heatpumps

How Klima Helps

Klima doesn’t replace proper servicing or repairs; it’s there to help you catch problems with your mini-split’s earlier.

With Klima’s Health Monitoring feature, you get alerts of issues occurring with your mini-split via the Boldr Energy app helping you stay proactive.

Check out Klima here: https://shopboldr.com/products/klima

FAQs

1. What does the error code E0 mean on a Mitsubishi mini split?

E0 often means a communication error between the indoor and outdoor Mitsubishi mini split. Check wiring, reset power, ensure connections are solid.

2. How often should I clean filters to avoid error codes?

Clean filters every month or more often if environment is dusty or you have animals. This helps avoid airflow issues and many error codes.

3. Can I fix refrigerant-related error codes myself?

No. Refrigerant work is technical and often regulated. If error codes suggest refrigerant pressure problems, call a trained technician.

Klima - Smart Home Thermostat for Mini-splits, Air Conditioners and Heatpumps

Wrapping Up

Mitsubishi mini split troubleshooting isn’t as scary as it looks. Error codes are like little clues that guide you toward what needs attention. A quick reset, a filter cleaning, or a drain check can solve many issues. 

For the more complex mini split, a professional is the best call. With regular care and a touch of smart enhancement from Klima, your Mitsubishi mini split can keep running smoothly for years.

Error codes are reminders, not disasters.

Mitsubishi Mini-Split Troubleshoot: Error Codes Guide

Klima - Smart Home Thermostat for Mini-splits, Air Conditioners and Heatpumps

Compatible with all brands of ACs and Mini-Splits Automate Climate Management   Control remotely   Reduce Energy Consumption   Monitor bills in realtime

Try Now

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