Code WN09: SEQUENCE PROGRAM IS NOT WRITTEN TO FLASH ROM
Issue Description & Safety Warning
The Fanuc 0i-D / 0i Mate-D Alarm List has triggered a critical SEQUENCE PROGRAM IS NOT WRITTEN TO FLASH ROM alarm. Immediate attention from a qualified operator or maintenance technician is required to prevent secondary damage to the equipment or spoiled parts during the manufacturing cycle. Always ensure standard safety and LOTO procedures are followed before accessing electrical cabinets.
Official Troubleshooting Steps
Section: PMC alarm list If you want to use a changed sequence You have changed the sequence program again next time you power on the program using the LADDER system, write the sequence program to DIAGRAM EDITOR screen or DATA flash ROM. If you have made any I/O screen, but you have not yet unwanted change to the sequence written the changed sequence program by mistake, read the original program to flash ROM. If you shut sequence program from flash ROM. down the system without writing the changed sequence program to flash ROM, the changes you have made will be nowhere next time you turn on the power.
Source: Fanuc B-64305EN/03 Appendix A Alarm List
Last reviewed: 2026-07-01 · Verified against the manufacturer’s official documentation.
About Fanuc 0i-D / 0i Mate-D Alarm List Alarms
Fanuc controllers include extensive self-diagnostics that flag or halt the machine when a fault is detected. Error code WN09 on the 0i-D / 0i Mate-D Alarm List identifies one specific fault condition — its documented cause and the official corrective steps are listed above, sourced from Fanuc's service documentation. Always confirm against the manual for your exact machine configuration and follow LOTO procedures before servicing.
Complete Alarm List: 769 Fanuc 0i-D / 0i Mate-D Alarm List codes.
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