Code 231-B300: CC%2 No brake line test was conducted %1
Issue Description & Safety Warning
The Heidenhain TNC Series CNC has triggered a critical CC%2 No brake line test was conducted %1 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] - MC (A channel) makes no test of the brake line, although the machine parameter setting requires it. - Timeout when calling for test of the brake control by the MC. - An axis was deselected by PLC module, although the corresponding machine parameter for running the brake line test is still set. [Error correction] - Check the machine parameter for testing the brake control or brake test - Generate the service files and notify the Service Department 10/2023 [479]
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-B300 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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