Yaskawa GA500 AC Drive
Yaskawa GA500 AC Drive code EF4: External Fault (Terminal S4)
An external device triggered a fault on terminal S4, causing the drive to stop the motor.
- Code
- EF4
- Name
- External Fault (Terminal S4)
- Controller
- Yaskawa GA500 AC Drive
- Type
- Safety interlock
- What it does
- Fault: the equipment trips and stops
- Risk
- YELLOW Booth plays by its own rules
- 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
- The step by step check for this problem, one check at a time
- 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 EF4 mean?
An external device triggered a fault on terminal S4, causing the drive to stop the motor.
Is Yaskawa GA500 AC Drive code EF4 dangerous?
It is graded yellow: not hard, but a booth does it differently than the gear most techs know, so follow the checks in order.
How do I fix Yaskawa GA500 AC Drive code EF4?
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
EF0 · Option Card External FaultEF1 · External Fault (Terminal S1)EF2 · External Fault (Terminal S2)EF3 · External Fault (Terminal S3)EF5 · External Fault (Terminal S5)EF6 · External Fault (Terminal S6)EF7 · External Fault (Terminal S7)Err · EEPROM Write ErrorFbH · Excessive PID FeedbackFbL · PID Feedback Loss