1172

RAM ERROR

Mitsubishi Electric · MELSEC System Q/L Series

What does 1172 mean?

The RAM of the CPU module (built-in I/O) is faulty. This error indicates a hardware problem with the internal memory specifically allocated for built-in I/O functions within the CPU module. It is detected at power ON or during a system reset.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Take noise reduction measures.

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Verified technical data. Last updated: March 2026

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Source: Mitsubishi Electric MELSEC System Q/L Series