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When your mini-split air conditioner malfunctions, you may notice an error code—a mix of letters and numbers—appearing on the display panel.These codes are part of the unit’s self-diagnosis system, designed to help users and technicians quickly identify what’s wrong. Like TOSOT, we are a sub-brand of GREE Appliance, which means we share the same error code system and diagnostic logic as our parent company. So, if you’ve ever searched for GREE mini split error codes, this guide will apply to your TOSOT mini split AC unit as well.

In this guide, we’ll explain the meaning behind the most common error codes (like F0, H5, and E8) for sinlge-zone unit, how to perform simple troubleshooting, and practical maintenance tips to help prevent these issues from happening again.

TOSOT Mini-Split AC Error Code Overview

Before diving into detailed troubleshooting, here’s a quick reference table for the most common mini-split AC error codes. Use this chart to identify what each code means and which component it affects

TOSOT Common Mini-Split AC Error Codes Troubleshooting

F0: Refrigerant Protection / Cut-Off Protection

The F0 code is one of the most common alerts for ductless air conditioners. It indicates low refrigerant levels or a possible leak within the system. Typical symptoms include poor cooling and heating performance or ice freezing up on the evaporator coil. 

If a leak is suspected, turn off the system immediately and contact a certified HVAC technician for leak testing and refrigerant recharge.

H5: IPM (Intelligent Power Module) Protection

This error indicates that the compressor is drawing excessive current, often due to restricted airflow or unstable power supply. Check the following:

• Ensure filters and vents are clean and unobstructed.
• Confirm both liquid and gas valves are open.
• Test voltage using a multimeter (follow your model’s manual for safe readings). If the voltage or current is outside normal range, stop using the unit and call a professional.

H3 / E8: Overload Protection

If the split AC unit overheats or the airflow is restricted, you may see H3 or E8. To reset:

1. Turn off and unplug the unit for several minutes.
2. Restart the system. If the error reappears, inspect for blocked vents, dirty coils, or other airflow issues.

L3: Outdoor DC Fan Motor Malfunction

Causes may include a jammed fan blade, loose connection, or blocked condenser. You can:

1. Turn off power.
2. Clean the outdoor unit and ensure the fan spins freely.
3. Reset the breaker.

For cleaning tips, check our related post: How to Deep Clean Mini-Split Indoor and Outdoor Units Without Removing Them.

E6: Communication Malfunction

This error usually occurs in new installations when the indoor and outdoor units lose signal connection. 

Check the following:

• The wiring between the two units — ensure each wire is connected to the correct terminal.
• Whether the signal cable is broken or has a short circuit.
• That all terminals are securely tightened..

H6: No Feedback from Indoor Fan Motor

This error indicates that the indoor fan motor is not providing feedback to the control board. The fan may be blocked or have a loose wire connection.

Check the following:

• Turn off power to the split AC unit.
• Gently spin the fan manually to see if it moves freely.
• Inspect for dust buildup, debris, or obstructions.
  If the fan does not spin smoothly, reassemble or tighten components as needed.

H7: Compressor Desynchronization

This code often relates to pressure or voltage irregularities. If power has fluctuated, turn off the unit, wait for the supply to stabilize, and restart. If the error persists, a part replacement (compressor module or board) may be required.

F1 / F2 / F4: Temperature Sensor Malfunction

These indicate issues with the temperature sensors. Try resetting by disconnecting power for a few minutes.If the code returns, the sensor may need replacement.

PL: DC Bus Voltage Too Low

This protection code occurs when the DC bus voltage falls below the safe operating threshold. Check that your wire connections are secure and that voltage readings are within the required range (L/N). Low voltage can trigger this protection mode to safeguard internal components.

Understanding Error Codes = Faster Fixes

These are the most common error codes encountered by our mini-split owners. While some can be temporarily reset or visually checked, others indicate deeper electrical or refrigerant issues. You can also refer to your manufacturer’s service manual for a complete error code list and detailed wiring diagrams.

→Download the service manual for TOSOT Single Zone AC

⚠️ Important Safety Reminder

While simple checks (like cleaning filters or confirming power) are safe for most homeowners, do not attempt to open or repair electrical components yourself. Always contact a certified HVAC technician for refrigerant or circuit-related repairs.

Preventing Error Codes: Maintenance Tips

While error codes help identify problems, the best way to avoid them is preventive maintenance. Regular care not only keeps your mini-split running smoothly but also reduces the chance of sudden breakdowns and costly repairs. 

Here are some practical maintenance steps:

1. Clean or replace air filters every season.
   Dirty filters restrict airflow, making the system overwork and potentially trigger codes like E8 (overload) or H5 (overcurrent).
   
2. Inspect indoor and outdoor coils.
   Dust buildup on the coils can cause inefficient cooling and system stress. Use a soft brush or coil cleaner to remove dirt safely.
   
3. Keep the outdoor unit clear.
    Ensure there are no leaves, debris, or obstructions within at least 12–18 inches around the outdoor condenser. Restricted airflow can cause fan or compressor errors.
   
4. Check for unusual sounds or vibrations.
   Rattling noises or humming can indicate loose components or fan imbalance—address them early before they trigger protection codes.
   
5. Schedule annual professional servicing.
   Have a licensed HVAC technician inspect refrigerant levels, sensors, and electrical components. Early detection of minor leaks or wiring wear can prevent major failures later.

Tip: During seasonal changes—especially before summer or winter—run your unit for a few minutes and check for unusual performance or warning codes. A quick test can reveal issues before peak season use.

Related post: Mini Split Maintenance Tips For Longer Service Life

Mini-Split Error Code FAQ

Why does my mini-split show an error code even though it’s cooling fine?

Some codes appear as early warnings—the system detects irregular current or temperature fluctuations before they affect performance. It’s best to note the code, reset the system, and monitor whether it returns.

Do all brands use the same error codes?

Not exactly. While most brands have their own coding systems, many follow similar logic for protection and diagnostics. TOSOT, for example, is a sub-brand of GREE Appliance, so both brands share the same mini split error code system. That means the troubleshooting steps for GREE mini split error codes often apply directly to TOSOT units as well.

When should I call a professional?   Call for professional service if:

• The same error appears after resetting.
• You notice refrigerant leaks, electrical smells, or strange noises.
• The system shuts down automatically multiple times a day.

Timely intervention prevents larger mechanical or electrical damage and keeps your unit efficient for years to come. If you have any concerns or questions, please contact the technical team at support@tosotdirect.com for assistance.