Code 231-E029: CC%2 Test step not possible (ID=%3)
Issue Description & Safety Warning
The Heidenhain TNC Series CNC has triggered a critical CC%2 Test step not possible (ID=%3) 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] One of the following steps in the safety self-test is not possible in a drive system with DRIVE-CLiQ inverters due to the hardware. The safety selftest can be configured through safe machine parameters in the configuration datum with CfgSafety. [Error correction] The given ID number indicates the appropriate test that must be deactivated for a system with DRIVE-CLiQ inverters. ID = 100: Test of the brake control. Test the setting in machine parameter testNotBrakeLine. ID = 200: Cutout channel test via signals STO.A.G / STOS.A.G. Check the setting in machine parameter testNotStoGlobal. ID = 300: Cutout channel test via signals internal to the control. Test the setting in machine parameter testNotStoIntrnl. - Note: These settings must be changed only by the machine tool builder. - Inform your 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-E029 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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