Omron CJ/CS Series Error Code C400

Omron PLC & VFD Major Hardware

Model: CJ/CS Series | Code: C400

Applicable Systems
CJ/CS Series

Symptoms

The CJ/CS Series reports an internal overheat fault. The heatsink temperature exceeded the protection threshold and the drive tripped.

Possible Causes

  • Cooling fan failure or blocked airflow in the Omron enclosure
  • Ambient temperature exceeding the drive rated maximum
  • Drive mounted without adequate clearance for heat dissipation

Troubleshooting Steps

  1. Step 1: Check the cooling fan for operation and replace if not spinning
    Fan runs at full speed after replacement
  2. Step 2: Verify the ambient temperature around the drive is below the rated maximum
    Ambient temperature is within the rated range
  3. Step 3: Ensure the drive has at least 100mm clearance on all sides for airflow
    Airflow is unobstructed around the drive

How to Reset

To reset: Allow the drive to cool, fix the cooling issue, then reset the fault.

Source: Omron CJ/CS Series PLC Programming Manual, Omron Corporation

Category: PLC & VFD