E41
Inverter Power Transistor Overheat
Mitsubishi Electric · R410A Systems
What does E41 mean?
The power transistor module within the inverter circuit has overheated. This indicates excessive load, inadequate cooling, or an internal fault within the inverter, risking damage to the power electronics that drive the compressor.
Common Causes
- Inverter power transistor has overheated.
- Insufficient cooling for the inverter module.
- High ambient temperature affecting inverter operation.
- Overload on the compressor motor.
- Faulty cooling fan for the inverter.
Repair Steps & Checklist
Click steps to track your progress.
- 1
Check for obstructions or debris on the inverter heatsink and ensure cooling fans are operating correctly.
- 2
Measure compressor current on all phases to ensure it's within specifications for the operating conditions.
- 3
Verify that the ambient temperature around the inverter is within the manufacturer's specified design limits.
- 4
Check for signs of discoloration or burn marks on the inverter power transistor module or its surrounding PCB.
Verified technical data. Last updated: March 2026
Related Faults
Source: Mitsubishi Electric R410A Systems