Mitsubishi Electric AC Error Codes List and Fixes
Mitsubishi Electric AC Error Codes List and Fixes
Mitsubishi Electric air conditioners are widely used in homes, offices, and commercial buildings due to their advanced technology, reliability, and energy efficiency.
However, even high-quality HVAC systems can sometimes experience faults. When this happens, Mitsubishi Electric air conditioners display error codes to indicate the specific problem.
These diagnostic codes help HVAC technicians quickly identify faults related to:
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Temperature sensors
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Fan motors
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Refrigerant systems
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Compressor operation
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Electrical components
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Communication networks
Understanding Mitsubishi Electric AC error codes allows technicians to diagnose and fix issues quickly, reducing system downtime.
This guide provides a complete list of 60+ Mitsubishi Electric AC error codes with causes and fixes.
What Are Mitsubishi Electric AC Error Codes?
Mitsubishi Electric air conditioners include an advanced self-diagnostic system that continuously monitors system performance.
If a malfunction occurs, the system displays an error code on:
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Indoor unit display panel
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Wired remote controller
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Outdoor unit indicator lights
Each error code corresponds to a specific component or system fault.
By reading the code, technicians can quickly determine the cause of the problem and apply the appropriate solution.
How to Check Mitsubishi Electric AC Error Codes
Mitsubishi Electric air conditioners allow technicians to retrieve stored error codes using the remote controller.
Steps to Check Error Codes
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Turn on the AC unit.
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Press and hold the CHECK or TEST button on the remote controller.
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The display will show stored error codes.
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When the correct error code appears, the indoor unit will beep.
This diagnostic feature simplifies troubleshooting.
Mitsubishi Electric Indoor Unit Error Codes
Below are common Mitsubishi Electric indoor unit error codes.
P1 – Indoor Coil Temperature Protection
Cause:
Evaporator coil temperature too low.
Fix:
Check airflow and clean air filters.
P2 – Indoor Coil Freeze Protection
Cause:
Evaporator coil freezing.
Fix:
Inspect airflow and refrigerant levels.
P4 – Indoor Coil Sensor Error
Cause:
Faulty evaporator temperature sensor.
Fix:
Replace sensor.
P5 – Drain Pump Error
Cause:
Condensate drain pump malfunction.
Fix:
Inspect drain pump and drainage system.
P6 – Indoor Heat Exchanger Temperature Error
Cause:
Heat exchanger overheating.
Fix:
Check airflow and coil condition.
P8 – Indoor Fan Motor Error
Cause:
Indoor fan motor malfunction.
Fix:
Inspect fan motor wiring or replace motor.
Mitsubishi Electric Outdoor Unit Error Codes
Outdoor units monitor compressor and refrigerant system operation.
U0 – Low Refrigerant Pressure
Cause:
Refrigerant leakage or insufficient charge.
Fix:
Inspect refrigerant piping and recharge system.
U1 – High Pressure Protection
Cause:
High refrigerant pressure.
Fix:
Clean condenser coil and check refrigerant charge.
U2 – Power Supply Voltage Error
Cause:
Power supply voltage abnormal.
Fix:
Check electrical power supply.
U3 – Communication Error
Cause:
Communication failure between indoor and outdoor units.
Fix:
Check communication wiring.
U4 – Indoor Outdoor Communication Error
Cause:
Network communication failure.
Fix:
Inspect communication cable connections.
U5 – Remote Controller Communication Error
Cause:
Remote controller wiring problem.
Fix:
Check controller wiring.
Mitsubishi Electric Compressor Error Codes
Compressor faults are critical and require immediate attention.
E1 – Compressor Start Failure
Cause:
Compressor unable to start.
Fix:
Check inverter PCB and compressor wiring.
E2 – Compressor Overcurrent Protection
Cause:
Excessive compressor current.
Fix:
Inspect compressor and electrical components.
E3 – Compressor Lock Error
Cause:
Mechanical compressor failure.
Fix:
Replace compressor.
E4 – Compressor Temperature Protection
Cause:
High compressor temperature.
Fix:
Check refrigerant charge and condenser airflow.
E5 – Compressor Discharge Temperature Error
Cause:
Discharge temperature too high.
Fix:
Inspect refrigerant system.
Mitsubishi Electric Refrigerant System Error Codes
F1 – Refrigerant Leakage Detection
Cause:
Refrigerant leak.
Fix:
Inspect piping and repair leak.
F2 – Refrigerant Flow Error
Cause:
Expansion valve malfunction.
Fix:
Check expansion valve.
F3 – Suction Pressure Error
Cause:
Low suction pressure.
Fix:
Inspect refrigerant system.
F4 – Discharge Pressure Error
Cause:
High discharge pressure.
Fix:
Clean condenser coil.
F5 – Refrigerant Overcharge Protection
Cause:
Excess refrigerant.
Fix:
Adjust refrigerant charge.
Mitsubishi Electric Fan Motor Error Codes
Fan motors maintain airflow across coils.
L1 – Indoor Fan Motor Error
Cause:
Fan motor malfunction.
Fix:
Inspect motor wiring.
L2 – Indoor Fan Lock Error
Cause:
Fan blade obstruction.
Fix:
Remove obstruction.
L3 – Outdoor Fan Motor Error
Cause:
Outdoor fan motor failure.
Fix:
Replace motor.
L4 – Outdoor Fan Speed Error
Cause:
Fan motor driver malfunction.
Fix:
Inspect inverter board.
Mitsubishi Electric Communication Error Codes
C1 – Indoor communication error
C2 – Outdoor communication error
C3 – Indoor-outdoor communication failure
C4 – Remote controller communication error
C5 – Central controller communication error
Cause:
Communication wiring faults.
Fix:
Check wiring and connections.
Mitsubishi Electric Inverter Error Codes
I1 – Inverter PCB Error
Cause:
Inverter board malfunction.
Fix:
Replace inverter PCB.
I2 – Inverter Overcurrent Protection
Cause:
Excessive inverter current.
Fix:
Inspect compressor.
I3 – Inverter Overvoltage Protection
Cause:
High voltage supply.
Fix:
Check power supply stability.
I4 – Inverter Undervoltage Protection
Cause:
Low voltage supply.
Fix:
Inspect electrical system.
Additional Mitsubishi Electric AC Error Codes
Below are more Mitsubishi Electric AC error codes commonly encountered.
E6 – Indoor unit EEPROM error
E7 – Outdoor unit EEPROM error
E8 – Indoor PCB communication error
E9 – Outdoor PCB communication error
EA – Indoor unit address error
EB – Outdoor unit address error
EC – System configuration error
ED – Indoor power supply error
EE – Outdoor power supply error
EF – Heat exchanger sensor error
Extended Mitsubishi Electric Error Codes
Additional protection codes include:
F6 – High temperature protection
F7 – Low temperature protection
F8 – Compressor restart protection
F9 – Inverter module protection
FA – System overload protection
FB – Phase loss error
FC – Voltage imbalance error
FD – Refrigerant pressure abnormal
FE – Expansion valve error
FF – System communication timeout
Common Causes of Mitsubishi Electric AC Errors
Most faults occur due to several common problems.
Sensor Failures
Temperature sensors may fail due to electrical faults.
Refrigerant Leaks
Low refrigerant pressure can trigger system protection.
Electrical Issues
Voltage fluctuations can damage inverter boards.
Blocked Airflow
Dirty filters reduce airflow and cause overheating.
How to Reset Mitsubishi Electric AC Error Codes
To reset error codes:
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Turn off the air conditioner.
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Disconnect power supply.
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Wait 5 minutes.
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Restart the system.
If the error persists, further troubleshooting is required.
Mitsubishi Electric AC Maintenance Tips
Regular maintenance helps prevent error codes.
Recommended maintenance tasks include:
- Clean air filters regularly
- Inspect refrigerant lines
- Clean condenser coils
- Check electrical wiring
- Inspect fan motors
Preventive maintenance improves system reliability.
Benefits of Understanding AC Error Codes
Understanding error codes offers several advantages.
Faster Troubleshooting
Technicians can quickly identify problems.
Reduced System Downtime
Correct repairs restore cooling faster.
Lower Maintenance Costs
Early detection prevents major failures.
Frequently Asked Questions
What does U0 error mean in Mitsubishi Electric AC?
U0 indicates low refrigerant pressure caused by refrigerant leakage or insufficient refrigerant.
Why does Mitsubishi Electric AC show P5 error?
P5 error indicates drain pump malfunction.
What causes U1 high pressure error?
High pressure error occurs due to blocked condenser airflow or refrigerant overcharge.
How do I reset Mitsubishi Electric AC error codes?
Turn off the power supply for several minutes and restart the system.
How often should Mitsubishi Electric AC be serviced?
Mitsubishi Electric air conditioners should typically be serviced every 6 months.
Final Summary
Mitsubishi Electric air conditioners use advanced diagnostic systems that display error codes when faults occur.
Understanding these 60+ Mitsubishi Electric AC error codes with fixes helps technicians quickly diagnose problems and restore system operation.
Regular maintenance and proper troubleshooting ensure reliable AC performance.
Conclusion
Mitsubishi Electric air conditioners are known for their durability and advanced technology, but faults can still occur.
By understanding the Mitsubishi Electric AC error codes list and fixes, technicians can quickly identify problems and perform efficient repairs.
Proper maintenance ensures long-term system reliability and optimal cooling performance.
