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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.

1171

RAM ERROR

Mitsubishi Electric · MELSEC System Q/L Series

What does 1171 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 can occur at any time.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Take noise reduction measures.

Browse all codes in this manual (53)
Verified technical data. Last updated: April 2026

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1000CPU Down Error1001CPU Down Error with Device Access Issue1002CPU Down Error
Source: Mitsubishi Electric MELSEC System Q/L Series
Open Manual (Page 1311)Search more codes in this manual