Code F01649: Internal software error
Issue Description & Safety Warning
The Siemens SINAMICS G120 CU240S Drive has triggered a critical Internal software error 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
Reaction: OFF 2 (OFF 3) Acknowledge: Quit fault eg. via DI2 Cause: - r0949 = 1: Buffer overflow on checksum calculation for P1 parameter access functions. - r0949 = 2: Buffer overflow on checksum calculation for P2 parameter access functions. - r0949 = 3: Endless safety loop on P1. - r0949 = 4: Endless safety loop on P2. - r0949 > 100: Signal an internal or unexpected software fault. Only for Siemens internal diagnostics. Remedy: Contact hotline.
Source: SINAMICS G120 Control Units CU240S Faults and Alarms (Edition 05/2007)
Last reviewed: 2026-07-01 · Verified against the manufacturer’s official documentation.
About Siemens SINAMICS G120 CU240S Drive Alarms
Siemens controllers include extensive self-diagnostics that flag or halt the machine when a fault is detected. Error code F01649 on the SINAMICS G120 CU240S Drive identifies one specific fault condition — its documented cause and the official corrective steps are listed above, sourced from Siemens's service documentation. Always confirm against the manual for your exact machine configuration and follow LOTO procedures before servicing.
Complete Alarm List: 108 Siemens SINAMICS G120 CU240S Drive codes.
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