Yaskawa GA500 AC Drive
Yaskawa GA500 AC Drive code SToF: Safe Torque OFF Hardware
A hardware fault occurred in the safe disable circuit, which immediately stops the drive and shuts down the motor.
Safety first. This code involves a gas, flame or electrical hazard. Do not keep resetting it. Leave burner, gas train and high voltage work to a qualified technician. WERCS answers 24/7 at (877) 489-3727.
- Code
- SToF
- Name
- Safe Torque OFF Hardware
- Controller
- Yaskawa GA500 AC Drive
- Type
- Internal fault
- What it does
- Fault: the equipment trips and stops
- Risk
- RED Specialist territory
- Reset
- Needs a manual reset
- 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 3 common causes 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 SToF mean?
A hardware fault occurred in the safe disable circuit, which immediately stops the drive and shuts down the motor.
Is Yaskawa GA500 AC Drive code SToF dangerous?
It is graded red, specialist territory: it involves a burner, gas, flame or safety lockout, so leave the repair to a qualified technician.
How do I fix Yaskawa GA500 AC Drive code SToF?
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
LT-3 · SoftChargeBypassRelay MainteTimeLT-4 · IGBT Maintenance Time (50%)PASS · Modbus Communication TestPWEr · DWEZ Password MismatchTrPC · IGBT Maintenance Time (90%)dCE1 · Communication Error1dCE2 · Communication Error2dFPS · Drive Model MismatchdWF1 · EEPROM Memory DWEZ Data ErrordWF2 · DriveWorksEZ Fault 2