E1

Fatal error

ABB · AC500

What does E1 mean?

This is a fatal error indicating that the safe function of the operating system is no longer guaranteed. It typically arises from critical issues such as a checksum error in the system Flash memory or a RAM error, compromising the CPU's core operations. This error demands immediate attention as the system will not operate reliably, potentially leading to unpredictable behavior or complete system failure.

Common Causes

  • Critical operating system failure impacting safe function.
  • Core system process has terminated unexpectedly.
  • Hardware malfunction preventing safe state verification.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Verify controller power supply voltage at terminal L1 and N is within specification (e.g., 24VDC).

  2. 2

    Inspect internal controller heatsink for debris or obstruction.

  3. 3

    Perform a full controller reboot by cycling power off for 60 seconds, then on.

  4. 4

    Check diagnostic logs for preceding error codes prior to this fatal error.

Browse all codes in this manual (54)
Verified technical data. Last updated: March 2026

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