CPU Fault

CPU error

Mitsubishi Electric · FR-E500 Inverter

What does CPU Fault mean?

The inverter's built-in CPU failed to complete an arithmetic operation within a predetermined timeframe, triggering an internal alarm and stopping the output. This indicates a critical internal processing error within the inverter.

Common Causes

  • Internal inverter hardware or software malfunction.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Perform a power cycle by switching the inverter's power supply off, waiting for at least 10 seconds, and then switching it back on.

  2. 2

    If the fault persists after a power cycle, contact a sales representative for further diagnosis, as this indicates a potential internal hardware failure.

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Verified technical data. Last updated: March 2026

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Source: Mitsubishi Electric FR-E500 Inverter