Code 201625: <location>SI CU: Sign-of-life error in safety data
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical <location>SI CU: Sign-of-life error in safety data 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
Message value: %1 Drive object: SERVO, VECTOR Reaction: OFF2 Acknowledge: IMMEDIATELY (POWER ON) Cause: The drive-based "Safety Integrated" function in the Control Unit (CU) has detected an error in the signof-life of the safety data between the CU and Motor Module (MM) and initiated a STOP A. - there is either a DRIVE-CLiQ communica tion error or communication has failed. - a time slice overflow of t he safety software has occurred. Fault value (r0949, interpret decimal): Only for internal Siemens troubleshooting. Remedy: - select Safe Torque Off and de-select again. - carry out a POWER ON (power off/on) for all components. - check whether there is a DRIVE-CLiQ communication error between the Control Unit and the Motor Module involved and, if required, carry out a diagnostics routine for the faults identified. - de-select all drive functions t hat are not absolutely necessary. - reduce the number of drives. - check the electrical cabinet design and cable routing for EMC compliance Note: CU: Control Unit MM: Motor Module SI: Safety Integrated
Source: SINUMERIK 840D sl / 840Di sl / SINAMICS S120 Diagnostics Manual (DAsl, 03/2009)
Last reviewed: 2026-07-01 · Verified against the manufacturer’s official documentation.
About Siemens SINUMERIK 840D CNC Alarms
Siemens controllers include extensive self-diagnostics that flag or halt the machine when a fault is detected. Error code 201625 on the SINUMERIK 840D CNC 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: 4014 Siemens SINUMERIK 840D CNC codes.
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