Code 201038: <location>ACX: Loading the parameter back-up file unsuccessful
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical <location>ACX: Loading the parameter back-up file unsuccessful 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: All objects Reaction: A_INFEED: NONE (OFF2) SERVO: NONE (OFF1, OFF2, OFF3) VECTOR: NONE (OFF1, OFF2, OFF3) Acknowledge: IMMEDIATELY SINAMICS-Alarms Cause: An error occurred when loading PSxxxyyy.ACX or PTxxxyyy.ACX file s from the CompactFlash card or from the volatile memory of the Control Unit. Fault value (r0949, interpret hexadecimal): Byte 1: yyy in the file name PSxxxyyy.ACX yyy = 000 --> consistency back-up file yyy = 001... 062 --> drive object number yyy = 099 --> PROFIBUS parameter back-up file Byte 4, 3, 2: Only for internal Siemens troubleshooting. Remedy: - If you have saved the project data using the commi ssioning software, carry out a new download for your project. Save using the function "Copy RAM to ROM" or with p0977 = 1 so that all of the parameter files are again completely written to the CompactFlash card. - replace the CompactFlash card.
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 201038 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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