Technician operating FANUC CNC testing benches during system inspection and repair at REACO CNC.

FANUC Alarm Code Guide

Find solutions to common Fanuc CNC alarm codes quickly and efficiently.

Servo Alarm
Spindle Alarm
System Alarm
Overtravel Alarm

FANUC Alarms: Quick Guide to Get Back Online​

When your FANUC CNC triggers an alarm, it's trying to tell you something. From simple overtravel to complex servo issues, these codes pinpoint where the problem lies.Our guide cuts through the complexity. We explain the most common alarms—what they mean, why they happen, and how to fix them. Whether you're facing alarm 401 or a stuck overtravel limit, you'll find clear, step-by-step solutions to minimize downtime.​​ You will learn how to:​​

  • Decode any FANUC alarm number.
  • Diagnose faults in servos, spindles, or system memory.
  • Perform basic checks before calling a technician.
  • Identify components that may need adjustment or replacement.

Get the knowledge to solve problems faster and keep your machines running.
FANUC CNC Alarm Troubleshooting Guide: Common Errors and Solutions
FANUC CNC systems are widely used in industrial automation, and alarms are an important part of system protection and diagnostics. Understanding the causes and solutions of common alarms can significantly reduce machine downtime and maintenance costs. This guide covers frequently encountered FANUC alarms, including external alarms, servo alarms, pneumatic system issues, and maintenance-related questions. 1. What is FANUC Alarm 2003? Cause Alarm 2003 is typically an external alarm, often displayed as EX2003, followed by a detailed message defined by the machine tool builder. For example: Insufficient lubrication Low pressure conditions... Read more...
FANUC 0i-D / 0i Mate-D Servo Alarm List and Troubleshooting Guide
FANUC CNC systems such as 0i Model D and 0i Mate-Model D are widely used in CNC machining centers and CNC lathes. During machine operation, the servo system may generate SV alarms (Servo Alarms) when abnormal conditions occur. These alarms can be caused by various factors such as: servo amplifier faults encoder communication errors parameter configuration issues power supply abnormalities FSSB communication failures mechanical load problems Understanding the meaning of these servo alarm codes can help technicians quickly diagnose machine problems and reduce downtime. This article provides a complete FANUC... Read more...
Fanuc Common Over Travel Alarm List (OT0500–OT0515)
During machine operation, if the motion exceeds the travel limits set in the FANUC system, an Over Travel Alarm will be triggered.These alarms serve to protect the machine from mechanical damage due to excessive travel or axis interference.This article summarizes the common Over Travel alarms (No. 500–515) and their troubleshooting methods. Common Overtravel Alarm Classification Below are the common FANUC Over Travel alarm codes and their meanings. Alarm No. Content Description 500 OVER TRAVEL : +n Exceeded the n–th axis + side stored stroke check I. (Parameter No.1320 or 1326) 501... Read more...
Common FANUC CNC Alarms Classification
During CNC machine operation, alarms may occasionally occur. To address these issues effectively, targeted troubleshooting and maintenance are required. This article provides a classification of common FANUC system alarms for reference, helping technicians respond correctly when problems arise. FANUC Alarm Classification FANUC system alarms refer to faults detected in CNC hardware or software. Alarms are classified according to their numbers as follows: Alarm Number Range Category 000~ Programming & Operation 300~ Pulse Encoder 400~ Servo 500~ Overtravel 700~ Overheat / Temperature Exception 749~ Spindle Communication 900~ CNC System 5000~ Programming... Read more...

Related Resources

Explore more technical materials to help you troubleshoot, maintain, and optimize your CNC system.

Related Links List：

Back to Main Technical Support
Close-up of a CNC machine cutting aluminum parts with high precision.

Need Technical Support or Repairs?

We offer repair services for all CNC parts, including systems, drives, motors, encoders, and PCBs. Fast repair, full testing, and REACO CNC warranty included. Contact us for guidance, troubleshooting, parameter support or repair.

 Tech Support