FALS E0.0 - CPU Hardware Error

Omron PLC & VFD Critical PLC

Model: Omron CJ2M PLC | Code: Omron E0.0

Applicable Systems
CJ/CS Series

Symptoms

CPU unit hardware fault detected; internal memory or CPU circuit failure; PLC stops all outputs.

Possible Causes

  • CPU unit internal memory failure (EEPROM/Flash)
  • Battery backup failure causing memory corruption
  • CPU internal circuit board fault

Troubleshooting Steps

  1. Step 1: Check CPU unit ERR indicator (solid red = fatal error)
    ERR indicator status
  2. Step 2: Replace CPU battery (if battery-related) and cycle power
    Battery replaced, power cycled
  3. Step 3: Attempt to download program backup to CPU
    Download succeeds if memory intact
  4. Step 4: If memory fault, replace CPU unit
    New CPU unit starts normally
  5. Step 5: Download backup program and verify I/O table
    Program running correctly

How to Reset

Replace CPU unit; requires program download from backup.

Common Replacement Parts

  • Omron CJ2M CPU Unit (model specific)
  • CPU Battery (3V lithium)

Frequently Asked Questions

  • Q: How often to replace Omron PLC battery?

    Every 3-5 years or when BAT indicator illuminates. Battery retains program and retentive data during power loss. Always keep program backup.

Related Omron Fault Codes

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Source: Omron CJ2M Operation Manual W394

Category: PLC & VFD