Fanuc FANUC 0i System Alarm 998

Fanuc CNC Critical ROM parity error

Model: FANUC Series 0 / 0i / 30i | Code: 998

Applicable Systems
Series 0i Series 16/18/21 Alpha Beta

Symptoms

A ROM parity error was detected.

Possible Causes

  • RAM/ROM hardware failure
  • CPU malfunction
  • Watchdog timer expired
  • Power supply or fuse fault

Troubleshooting Steps

  1. Step 1: Record all alarm information displayed on the CNC screen
    Complete alarm information captured
  2. Step 2: Power cycle the CNC system
    System restarts; check if alarm clears
  3. Step 3: If alarm persists, check the main board and servo boards for visible damage
    No visible damage or burn marks
  4. Step 4: Replace the faulty main board or servo board as indicated by the alarm
    New board eliminates the system alarm

How to Reset

To reset system alarm 998: 1) Record all alarm information. 2) Power cycle the CNC. 3) If alarm persists, replace the indicated board (main board, servo board, etc.). 4) Re-load all system parameters and programs. Caution: System alarms indicate serious hardware faults; professional service is recommended.

Frequently Asked Questions

  • Q: What does 998 mean on Fanuc FANUC 0/0i/30i Series?

    A ROM parity error was detected.

  • Q: How do I fix 998 on Fanuc?

    Follow the troubleshooting steps: Record all alarm information displayed on the CNC screen

Related Fanuc Fault Codes

Source: FANUC CNC System Alarm Manual (doc.eleok.com)

Category: CNC