Code 231-A210: Faulty control of brake %1: Step %4
Issue Description & Safety Warning
The Heidenhain TNC Series CNC has triggered a critical Faulty control of brake %1: Step %4 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
[Cause of error] - Incorrect signal level at the FS input: "-T.BRK.B" during brake control test Test step 2 = Release brake through B channel output: +24 V detected although T.BRK should provide 0 V Test step 3 = Release brake through A channel output: +24 V detected although T.BRK should provide 0 V Test step 4 = Release brake through A and B channel outputs: 0 V detected although T.BRK should provide +24 V [Error correction] - Check external wiring of the motor brake - Generate the service files and notify the service agency
Source: HEIDENHAIN NC Error Messages — TNC7/640/620/320/128, CNC PILOT 640, MANUALplus 620 (10/2023)
Last reviewed: 2026-07-01 · Verified against the manufacturer’s official documentation.
About Heidenhain TNC Series CNC Alarms
Heidenhain controllers include extensive self-diagnostics that flag or halt the machine when a fault is detected. Error code 231-A210 on the TNC Series CNC identifies one specific fault condition — its documented cause and the official corrective steps are listed above, sourced from Heidenhain's service documentation. Always confirm against the manual for your exact machine configuration and follow LOTO procedures before servicing.
Complete Alarm List: 4497 Heidenhain TNC Series CNC codes.
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