Code F01601: System startup error
Issue Description & Safety Warning
The Siemens SINAMICS G120 CU240S Drive has triggered a critical System startup error 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
Reaction: OFF 2 (OFF 3) Acknowledge: Power on Cause: System startup error. Error during the startup initialisation after a PowerCycle or HotSwap. This error is critical and cannot be acknowledged. A restart (hotswap or power cycle) of the drive is required! - r0949 = 0: Handshaking error on P1. Either an unexpected reboot by P1 or a synchronisation error during star- tup. Please power-cycle the inverter module again or perform a hotswap. - r0949 = 1: Handshaking error on P2. Either a faulty reboot by P2 or a synchronisation error during startup. Please power-cycle the inverter module or perform a hotswap. - r0949 = 100: Version error detected by P1. The safety version number is not identical on P1 and P2. - r0949 = 101: Startup semaphore is wrong on P1. Can happen if commissioning was not finished properly before performing a power cycle. There might also be a problem of the EEPROM. - r0949 = 102: Error with semaphore on P1. The drive loads default parameters instead of the user settings. - r0949 = 103: Error with initial and first hardware type detection on P1. The hardware type (standard or safety module) could not be identified. Either the control board is faulty or affected by EMC. - r0949 = 104: Timeout error on P1 while waiting for communication with P2. - r0949 = 105: Error on P1 during hardware exchange phase. Processors have not agreed on same type of hard- ware platform. - r0949 = 106: Timeout error on P1 in hardware detection state. Handshaking with P2 failed. - r0949 = 107: Checksum error on P1. The safety parameters are not consistent in EEPROM. - r0949 = 108: Error on P1 during parameter transfer to P2. The correct safety parameters are not available on P2 due to a communication problem. - r0949 = 109: Timeout error on P1 during parameter transfer to P2 due to different safety checksums on P1 and P2. The parameter transfer to P2 has failed. - r0949 = 110: Timeout error on P1 during forced dynamisation and processor self test. - r0949 = 111: Timeout error on P1 when leaving the safety commissioning at startup. - r0949 = 112: Checksum error on P1 during processor initialisation. - r0949 = 200: Version error detected by P2. The safety version number (see r9770) is not identical on P1 and P2. - r0949 = 201: Startup semaphore is wrong on P2. Can happen if commissioning was not finished properly before performing a power cycle. There might also be a problem of the EEPROM. - r0949 = 202: Error with semaphore on P2. The drive loads default parameters instead of the user settings. - r0949 = 203: Error on P2 with initial and first hardware detection. The hardware type (standard or safety mod- ule) could not be identified. Either the control board is faulty or affected by EMC. - r0949 = 204: Timeout error on P1 while waiting for communication with P2. - r0949 = 205: Error on P1 during hardware exchange phase. Processors have not agreed on same type of hard- ware platform. - r0949 = 206: Timeout error on P2 during hardware detection. Handshaking with P1 failed. - r0949 = 207: Checksum error on P2. The safety parameters on P2 are not consistent. - r0949 = 208: Error on P2 during parameter transfer from P1. The safety parameters on P2 are not valid due to a communication problem. - r0949 = 209: Timeout error on P2 during parameter transfer from P1. Possibly due to different checksums on P1 and P2. - r0949 = 210: Timeout error on P2 in startup dynamisation phase. The communication failed. - r0949 = 211: Timeout error on P2 when leaving the initial safety commissioning. - r0949 = 212: Checksum error on P2 during processor initialisation. Remedy: - Power-cycle CU (since fault F1601 cannot be acknowledged). - Make sure that CU is connected correctly to PM. - Reduce EMC.
Source: SINAMICS G120 Control Units CU240S Faults and Alarms (Edition 05/2007)
Last reviewed: 2026-07-01 · Verified against the manufacturer’s official documentation.
About Siemens SINAMICS G120 CU240S Drive Alarms
Siemens controllers include extensive self-diagnostics that flag or halt the machine when a fault is detected. Error code F01601 on the SINAMICS G120 CU240S Drive 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: 108 Siemens SINAMICS G120 CU240S Drive codes.
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