Mitsubishi Heavy Industries Error Codes
MHI (SRK / FDT / KX) shows E-codes on the wired controller; outdoor LEDs flash a green/red pattern.
E1
Remote controller communication error
- Cause:
- RC cable broken or wrong address
- Action:
- Check 2-core RC wiring and controller settings.
E5
Indoor ↔ outdoor signal transmission error
- Cause:
- Interconnect or PCB fault
- Action:
- Verify X-Y-earth interconnect, supply voltage and PCBs.
E6
Indoor heat exchanger sensor (Thi-R) fault
- Cause:
- Open / short pipe thermistor
- Action:
- Measure sensor resistance and replace.
E7
Indoor return air sensor (Thi-A) fault
- Cause:
- Open / short return sensor
- Action:
- Replace return air thermistor.
E8
Heating overload
- Cause:
- High condensing pressure, dirty indoor coil
- Action:
- Clean filters/coil, check airflow and charge.
E9
Drain trouble
- Cause:
- Drain pump or float switch fault
- Action:
- Clear drain, test pump and float.
E10
Too many indoor units on group control
- Cause:
- More than 16 units on one RC
- Action:
- Reduce group size or split network.
E16
Indoor fan motor fault
- Cause:
- Failed DC fan motor or PCB
- Action:
- Test motor windings and feedback, replace motor.
E19
Indoor unit address setting error
- Cause:
- Duplicate or missing address
- Action:
- Re-set DIP/auto address.
E28
Remote controller temperature sensor fault
- Cause:
- Sensor inside wired controller failed
- Action:
- Replace wired controller.
E35
Outdoor heat exchanger overheat
- Cause:
- Dirty condenser or fan fault in cooling
- Action:
- Clean condenser, check fan operation.
E36
Discharge pipe temperature high
- Cause:
- Low charge, EEV fault
- Action:
- Check charge, EEV and Td sensor.
E38
Outdoor air sensor (Tho-A) fault
- Cause:
- Open / short ambient sensor
- Action:
- Replace ambient sensor.
E39
Discharge pipe sensor (Tho-D) fault
- Cause:
- Open / short Td sensor
- Action:
- Replace discharge sensor.
E40
High pressure switch (63H1) activated
- Cause:
- Blocked condenser, overcharge, fan fault
- Action:
- Inspect condenser, fan, charge, EEV.
E42
Compressor current (CT) abnormal
- Cause:
- CT sensor or overcurrent
- Action:
- Check CT wiring and compressor current draw.
E59
Compressor start-up failure
- Cause:
- Locked rotor, IPM, low DC bus
- Action:
- Megger compressor, test inverter PCB.
For field guidance only. Codes and procedures vary by model and firmware — always confirm with the Mitsubishi Heavy Industries service manual for the specific unit before carrying out a repair.