E56
Power Transistor Thermistor Faulty or Disconnected
Mitsubishi Electric · FR-D700 Inverter
What does E56 mean?
The power transistor thermistor is faulty or disconnected (specific to FDCVA151-251 models), impacting temperature monitoring of the power transistors. This can lead to inverter damage from overheating.
Common Causes
- Disconnection of the power transistor thermistor.
- Open circuit fault in the power transistor thermistor sensor.
- Faulty power transistor thermistor indicating an incorrect temperature.
Repair Steps & Checklist
Click steps to track your progress.
- 1
Inspect the power transistor thermistor connection for dislodgement or damage, particularly on FDCVA151-251 models.
- 2
Measure the resistance of the thermistor to verify functionality and compare to the specified temperature-resistance chart.
- 3
Ensure the thermistor is securely connected to the inverter PCB and properly seated for accurate temperature sensing.
Verified technical data. Last updated: March 2026
Related Faults
Source: Mitsubishi Electric FR-D700 Inverter