Mitsubishi Heavy Industries AC Error Codes List and Fixes
Mitsubishi Heavy Industries AC Error Codes List and Fixes
Mitsubishi Heavy Industries (MHI) air conditioners are widely used in residential and commercial HVAC systems due to their reliability, energy efficiency, and advanced technology.
However, like any air conditioning system, MHI air conditioners may display error codes when the system detects abnormal operation.
These error codes help technicians quickly identify faults related to:
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Temperature sensors
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Fan motors
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Refrigerant pressure
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Compressor operation
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Communication systems
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Electronic control boards
Understanding Mitsubishi Heavy Industries AC error codes helps HVAC technicians diagnose and fix problems quickly.
This guide provides a complete list of 60+ MHI AC error codes with causes and solutions.
What Are Mitsubishi Heavy Industries AC Error Codes?
MHI air conditioners include an advanced self-diagnostic system that continuously monitors system performance.
When a fault occurs, the system displays an error code on:
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Indoor unit display
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Wired remote controller
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Outdoor unit indicator lights
Each code corresponds to a specific problem within the air conditioning system.
By identifying the error code, technicians can quickly determine the cause and perform the correct repair.
How to Check Mitsubishi Heavy Industries AC Error Codes
Technicians can retrieve 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 the CHECK or TEST button on the remote controller.
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The display will show stored error codes.
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The indoor unit will beep when the correct code appears.
This diagnostic feature helps simplify troubleshooting.
Mitsubishi Heavy Industries Indoor Unit Error Codes
Below are common indoor unit error codes and solutions.
E0 – Indoor Unit Communication Error
Cause:
Communication failure between indoor and outdoor units.
Fix:
Check communication wiring and PCB connections.
E1 – Indoor Control Board Error
Cause:
Indoor PCB malfunction.
Fix:
Inspect control board and replace if necessary.
E2 – Indoor Room Temperature Sensor Error
Cause:
Faulty room temperature sensor.
Fix:
Replace temperature sensor.
E3 – Indoor Coil Temperature Sensor Error
Cause:
Evaporator coil sensor malfunction.
Fix:
Inspect sensor wiring or replace sensor.
E4 – Indoor Fan Motor Error
Cause:
Fan motor malfunction or obstruction.
Fix:
Check motor wiring or replace motor.
E5 – Indoor EEPROM Error
Cause:
Indoor control memory failure.
Fix:
Replace indoor PCB.
Mitsubishi Heavy Industries Outdoor Unit Error Codes
Outdoor units monitor compressor and refrigerant system performance.
E6 – Outdoor Unit Communication Error
Cause:
Communication failure between indoor and outdoor units.
Fix:
Check communication wiring.
E7 – Outdoor Temperature Sensor Error
Cause:
Outdoor air temperature sensor malfunction.
Fix:
Replace temperature sensor.
E8 – Outdoor Coil Sensor Error
Cause:
Condenser coil temperature sensor failure.
Fix:
Inspect wiring or replace sensor.
E9 – Outdoor Fan Motor Error
Cause:
Outdoor fan motor malfunction.
Fix:
Inspect fan motor and replace if necessary.
E10 – Outdoor PCB Error
Cause:
Outdoor control board malfunction.
Fix:
Replace PCB.
Mitsubishi Heavy Industries Compressor Error Codes
Compressor errors significantly affect cooling performance.
E11 – Compressor Overcurrent Protection
Cause:
Compressor drawing excessive current.
Fix:
Check compressor wiring and inverter board.
E12 – Compressor Start Failure
Cause:
Compressor unable to start.
Fix:
Inspect inverter PCB and compressor connections.
E13 – Compressor Lock Error
Cause:
Compressor mechanical failure.
Fix:
Replace compressor.
E14 – Compressor Temperature Protection
Cause:
High compressor temperature.
Fix:
Check refrigerant charge and condenser airflow.
Mitsubishi Heavy Industries Refrigerant Error Codes
Refrigerant system faults are common causes of AC errors.
E15 – High Pressure Protection
Cause:
Excessive refrigerant pressure.
Fix:
Clean condenser coil and check refrigerant charge.
E16 – Low Pressure Protection
Cause:
Low refrigerant level or leakage.
Fix:
Inspect piping and recharge refrigerant.
E17 – Refrigerant Flow Error
Cause:
Expansion valve malfunction.
Fix:
Inspect electronic expansion valve.
E18 – Discharge Temperature Error
Cause:
High compressor discharge temperature.
Fix:
Check airflow and refrigerant charge.
Mitsubishi Heavy Industries Fan Motor Error Codes
Fan motors maintain airflow across coils.
E19 – Indoor Fan Lock Error
Cause:
Fan blade obstruction.
Fix:
Remove obstruction and inspect motor.
E20 – Indoor Fan Speed Error
Cause:
Fan motor speed abnormal.
Fix:
Inspect motor driver.
E21 – Outdoor Fan Lock Error
Cause:
Outdoor fan motor jam.
Fix:
Check fan motor and replace if needed.
Mitsubishi Heavy Industries Communication Error Codes
E22 – Indoor Outdoor Communication Error
Cause:
Communication wiring fault.
Fix:
Inspect cables and connectors.
E23 – Remote Controller Communication Error
Cause:
Remote controller wiring problem.
Fix:
Check controller cable.
E24 – Central Controller Communication Error
Cause:
Network communication failure.
Fix:
Inspect system communication network.
Mitsubishi Heavy Industries Inverter Error Codes
E25 – Inverter PCB Error
Cause:
Inverter board malfunction.
Fix:
Replace inverter PCB.
E26 – Inverter Overcurrent Protection
Cause:
Excessive inverter current.
Fix:
Inspect compressor and inverter board.
E27 – Inverter Overvoltage Error
Cause:
High voltage supply.
Fix:
Check power supply stability.
E28 – Inverter Undervoltage Error
Cause:
Low voltage supply.
Fix:
Inspect electrical supply.
Additional Mitsubishi Heavy Industries Error Codes
Below are more MHI AC error codes commonly encountered by technicians.
E29 – Indoor unit address error
E30 – Outdoor unit address error
E31 – System configuration error
E32 – Indoor power supply error
E33 – Outdoor power supply error
E34 – Heat exchanger sensor error
E35 – Refrigerant sensor error
E36 – Compressor inverter error
E37 – Outdoor fan inverter error
E38 – Indoor PCB communication error
Extended Mitsubishi Heavy Industries Error Codes
Additional system protection codes include:
E39 – System overload protection
E40 – Refrigerant leak detection
E41 – Expansion valve error
E42 – Indoor unit freeze protection
E43 – Outdoor unit overheat protection
E44 – Compressor restart protection
E45 – Voltage imbalance error
E46 – Phase loss error
E47 – High temperature protection
E48 – Low temperature protection
Mitsubishi Heavy Industries VRF System Error Codes
For MHI VRF systems:
E49 – VRF communication error
E50 – VRF indoor unit error
E51 – VRF outdoor unit error
E52 – VRF refrigerant pressure error
E53 – VRF inverter module error
E54 – VRF compressor synchronization error
E55 – VRF fan motor error
E56 – VRF system protection mode
E57 – VRF sensor calibration error
E58 – VRF address conflict error
E59 – VRF network communication failure
E60 – VRF controller error
Common Causes of Mitsubishi Heavy Industries AC Errors
Most MHI air conditioner faults occur due to several common issues.
Sensor Failures
Temperature sensors may fail due to electrical faults.
Refrigerant Leaks
Low refrigerant levels trigger system protection.
Electrical Problems
Voltage fluctuations can damage inverter boards.
Dirty Filters
Blocked airflow causes overheating.
How to Reset Mitsubishi Heavy Industries AC Error Codes
To reset MHI AC 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 code persists, further troubleshooting is required.
Mitsubishi Heavy Industries AC Maintenance Tips
Regular maintenance helps prevent AC 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 Cost
Early detection prevents major failures.
Frequently Asked Questions
What does E0 error mean in Mitsubishi Heavy Industries AC?
E0 indicates communication failure between indoor and outdoor units.
Why does Mitsubishi Heavy Industries AC show E4 error?
E4 error usually indicates indoor fan motor malfunction.
What causes E15 high pressure error?
High pressure error occurs due to blocked condenser airflow or refrigerant overcharge.
How do I reset Mitsubishi Heavy Industries AC error codes?
Turn off the power supply for several minutes and restart the system.
How often should Mitsubishi AC be serviced?
Mitsubishi air conditioners should typically be serviced every 6 months.
Final Summary
Mitsubishi Heavy Industries air conditioners include advanced diagnostic systems that display error codes when faults occur.
Understanding these 60+ Mitsubishi Heavy Industries AC error codes with fixes helps technicians diagnose problems quickly and restore system performance.
Proper maintenance and timely troubleshooting ensure reliable AC operation.
Conclusion
Mitsubishi Heavy Industries air conditioners are known for their reliability and advanced technology. However, error codes may appear when system faults occur.
By understanding the MHI AC error codes list and fixes, technicians can quickly identify and repair problems, ensuring efficient and reliable air conditioning performance.
