4186H

System Error - Abnormal OS Argument Data

Mitsubishi Electric · MELSEC System Q/L Series

What does 4186H mean?

An abnormality was detected in the argument data within the Operating System (OS). This indicates a system error that could stem from improper installation of hardware, an unsuitable operating environment, insufficient power supply, or a hardware failure of the CPU module itself.

Common Causes

  • Power supply module or CPU module not properly installed to the base unit.
  • Operating environment for the system does not satisfy the general specifications of the CPU module.
  • Insufficient power capacity.
  • Hardware failure of the CPU module.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Check whether the power supply module and the CPU module are properly installed to the base unit.

  2. 2

    Verify that the operating environment for the system satisfies the general specifications of the CPU module.

  3. 3

    Check whether the power capacity is sufficient for all connected components.

  4. 4

    Reset the CPU module.

  5. 5

    If the same error code is displayed again, diagnose for a hardware failure of the CPU module.

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

Related Faults

Source: Mitsubishi Electric MELSEC System Q/L Series