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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.

1439

MULTI-C.BUS ERR.

Mitsubishi Electric · MELSEC System Q/L Series

What does 1439 mean?

An error of the multiple CPU high speed main base unit was detected. This refers to an error of the multiple CPU high speed bus, indicating a problem with the physical chassis or the communication backbone in a multi-CPU system.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Reset the CPU module and RUN it again. If the same error is displayed again, the CPU module has hardware failure.

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 1318)Search more codes in this manual