Code 206906: <location>Braking Module internal fault
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical <location>Braking Module internal fault 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: B_INF Reaction: NONE Acknowledge: IMMEDIATELY SINAMICS-Alarms Diagnostics Manual (DAsl), 03/2009 Cause: The internal Braking Module outputs a fault due to over current or an excessively high I2t value and is therefore inhibited. Note: This message is also displayed via BO: p3686. Fault value (r0949, interpret bitwise binary): Bit 0 = 1: I2t exceeded Bit 1 = 1: overcurrent See also: r3686 (Digital Braking Module Fault) Remedy: Reduce the number of braking operations.
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 206906 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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