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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.

7003

Multiple CPU Initial Communication Stage Error

Mitsubishi Electric · MELSEC System Q/L Series

What does 7003 mean?

This error indicates a lack of response from a target CPU module during the initial communication stage within a multiple CPU system. This diagnostic occurs at power ON or reset. If this error persists after basic troubleshooting, it suggests a potential hardware fault within one of the CPU modules. The system will stop.

Common Causes

  • No response from the target CPU module during the initial communication stage in a multiple CPU system.
  • Potential hardware fault of any CPU module if the error reoccurs after reset.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Reset the CPU module and attempt to transition it to RUN mode again.

  2. 2

    Verify the power supply and physical mounting of all CPU modules within the multiple CPU system.

  3. 3

    Inspect the tracking cable connections for damage or incorrect seating if applicable to the system configuration.

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
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