Siemens G120 F01000 — What It Means
Fault F01000 on a Siemens SINAMICS G120 indicates an internal software error inside the drive’s control electronics, not a motor overload or power circuit problem. The drive stops with an OFF2 reaction and requires a full POWER ON reset to acknowledge the fault. This is a Control Unit issue, not a Power Module fault. The error points to corruption or failure in the drive’s internal software or non-volatile memory. Siemens classifies this as an internal troubleshooting code, meaning the root cause often requires factory-level diagnostics or Control Unit replacement if standard resets do not clear it.
Common Causes
- Internal software error in the Control Unit The drive’s control electronics have experienced a software fault or invalid internal data condition.
- Firmware corruption The drive’s firmware has become corrupted or contains a bug that triggers the internal error.
- Non-volatile memory failure Data stored in the drive’s memory or memory card has become corrupted or unreadable.
- Control Unit hardware failure The Control Unit itself has developed an internal fault that prevents normal software operation.
- Invalid parameter data after power loss A sudden power interruption or brown-out left the drive with incomplete or invalid stored parameters.
Step-by-Step Fix {#fix}
- Read the fault buffer using parameter r0945 on the keypad or via STARTER software to view the complete fault history and any additional context codes.
- Remove all power from the drive and wait at least 5 minutes for the internal capacitors to fully discharge.
- Restore power and observe whether the fault clears automatically or reappears immediately on startup.
- Check the memory card (if installed) for physical damage or corruption and reseat or replace it if suspect.
- Update the firmware to the latest approved version for your G120 model using STARTER or the appropriate Siemens service tool.
- Replace the Control Unit if the fault persists after a full power cycle and firmware update, as this indicates a hardware failure in the control electronics.
- Contact Siemens technical support or use factory service tools if the fault continues after Control Unit replacement, as deeper internal diagnostics may be required.
Parts Often Needed
| Part | Notes |
|---|---|
| Siemens G120 Control Unit (CU) | Amazon | Match the exact CU model and firmware version to your drive frame size and application. |
| Siemens MMC memory card | Amazon | Replacement if the existing card is corrupted or causing parameter storage errors. |
When to Call a Pro
Call a qualified drive technician or Siemens service partner if the fault returns after a complete power cycle, if you are not trained to update firmware or handle Control Unit replacement, or if the drive is part of a safety-rated or mission-critical system. Because F01000 is an internal software error, factory-level diagnostics or replacement of the Control Unit is often the only permanent fix. If your facility does not have STARTER software, proper ESD procedures, or spare Control Units on hand, professional service will save time and prevent further damage to the drive or process.