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ErrorLib — Industrial Fault Code Library

Disclaimer: ErrorLib is an independent technical reference tool. While we aim for accuracy, always verify with the manufacturer’s official service manuals before performing maintenance on industrial equipment. ErrorLib is not affiliated with the brands listed.

F01655

Fault at processor reset

Siemens · SINAMICS G120

What does F01655 mean?

This fault indicates a timeout during a safety reset operation on either the P1 or P2 processor, meaning the system failed to reset within the expected timeframe. This can prevent the drive from reinitializing correctly, often caused by an unexpected system hang during the reset process.

Common Causes

  • Internal watchdog timeout on either the safety P1 or P2 processor during a reset sequence, indicating a non-responsive CPU.
  • Corrupt firmware image or bootloader preventing one of the safety processors from initializing correctly after a reset command.
  • Insufficient or unstable internal power supply voltage (e.g., 3.3V, 5V) to the safety processor module during the reset phase.
  • Hardware failure of the safety processor module itself, preventing proper boot-up sequence.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    1. Cycle main power to the drive (full power-off/power-on cycle) and observe if the fault clears upon restart.

  2. 2

    2. Check for any available firmware updates for the drive's safety module and perform an update if necessary, ensuring full parameter backup first.

  3. 3

    3. Monitor internal diagnostic LEDs on the safety module (if present) for specific boot sequence or error indications.

  4. 4

    4. Verify the 24VDC control supply voltage at designated terminals (e.g., X9/X10) remains stable during power-up and reset attempts.

  5. 5

    5. Access drive diagnostics via the HMI or engineering tool to check status registers related to safety processor boot (e.g., r9790, r9791).

Browse all codes in this manual (109)
Verified technical data. Last updated: April 2026

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Source: Siemens SINAMICS G120
View Official PDFSearch more codes in this manual