Yaskawa GA500 AC Drive
Yaskawa GA500 AC Drive code LT-4: IGBT Maintenance Time (50%)
The insulated gate bipolar transistor is at half of its expected performance life, and the drive continues operating normally.
- Code
- LT-4
- Name
- IGBT Maintenance Time (50%)
- Controller
- Yaskawa GA500 AC Drive
- Type
- Internal fault
- What it does
- Warning: the equipment keeps running and flags a problem
- Risk
- GREEN In your wheelhouse
- Reset
- Clears on its own when the condition goes away
- Source
- The manufacturer's manual (subscribers see which manual and page)
Updated November 4, 2026
How to fix it
Subscribers get:
- What to do next, in plain words
- What the manual says to do, and the page it is on
- The 1 common cause listed for this code
- Booking a live video call with Ben, a master booth technician ($250/hr, paid per call)
Questions about this code
What does Yaskawa GA500 AC Drive code LT-4 mean?
The insulated gate bipolar transistor is at half of its expected performance life, and the drive continues operating normally.
Is Yaskawa GA500 AC Drive code LT-4 dangerous?
It is graded green: in a working tech's wheelhouse with standard tools and low risk.
How do I fix Yaskawa GA500 AC Drive code LT-4?
The manual's fix and the step by step check for this code are in WERCS Diagnose, plans from $49 a month. For help right now, WERCS answers 24/7 at (877) 489-3727.
Other Yaskawa GA500 AC Drive codes
L24v · Loss of External Power 24 SupplyLT-1 · Cooling Fan Maintenance TimeLT-2 · Capacitor Maintenance TimeLT-3 · SoftChargeBypassRelay MainteTimePASS · Modbus Communication TestPWEr · DWEZ Password MismatchSToF · Safe Torque OFF HardwareTrPC · IGBT Maintenance Time (90%)dCE1 · Communication Error1dCE2 · Communication Error2