00A12H

Failure of Disabling Safety Module

Mitsubishi Electric · MELSEC iQ-R I/O Module

What does 00A12H mean?

This event code is registered in the event history if the attempt to disable the safety module function of the I/O module with diagnostic functions fails. This means 'Enable (1)' remains in Validation status area (Un\G5377) and the ALM LED does not flash (400ms cycle), preventing normal operation.

Common Causes

  • The attempt to disable the safety module function of the I/O module with diagnostic functions was unsuccessful.
  • An incorrect value was set in Command area for module invalidation (Un\G5376) prior to the disable attempt.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Check that the set value in Command area for module invalidation (Un\G5376) is correctly set to 1234H.

  2. 2

    Turn on and off 'Operating condition setting request' (Y12) again.

  3. 3

    Check Validation status area (Un\G5377) to confirm that 'Disable (0)' is now stored.

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Verified technical data. Last updated: March 2026

Related Faults

Source: Mitsubishi Electric MELSEC iQ-R I/O Module