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.
Complete FANUC Spindle Alarm Codes (SP9110–SP9216)
This page provides the complete FANUC serial spindle alarm list (final section), covering alarm codes from SP9110 to SP9216. These alarms mainly relate to: Power supply (PS) faults Communication errors Safety system issues Hardware failures and protection functions This section is essential for advanced troubleshooting and maintenance of FANUC CNC systems. FANUC Spindle Alarm List (SP9110–SP9216) 1) SP9110 – SP9113 Alarm Code Message Amplifier Display Cause Troubleshooting SP9110 Amplifier Communication Error B0 Communication failure between spindle amplifier and power supply Replace communication cable or unit SP9111 Inverter Control Voltage Low... Read more...
FANUC Spindle Alarm Codes (SP9034–SP9092)
This page continues the FANUC serial spindle alarm list, covering alarm codes from SP9034 to SP9092. These alarms mainly involve: Parameter errors Encoder and sensor faults Spindle synchronization issues Communication and hardware failures Understanding these alarms helps reduce downtime and improve CNC machine reliability. FANUC Spindle Alarm List (SP9034–SP9092) 1) SP9034 – SP9043 Alarm Code Message Amplifier Display Cause Troubleshooting SP9034 SSPA:34 Parameter Illegal 34 Parameter value exceeds allowable range Refer to parameter manual and correct values SP9036 SSPA:36 Error Counter Overflow 36 Position error counter overflow Reduce position gain... Read more...
FANUC Serial Spindle Alarm Codes (SP9001–SP9033)
When a serial spindle alarm occurs in a FANUC CNC system, the CNC displays an alarm number for diagnosis. If the red LED on the spindle amplifier lights up, a two-digit alarm code is shown. ⚠️ Important Notes: A yellow LED indicates a sequence-related issue, not a hardware fault Example: spindle rotation command issued while emergency stop is active Alarm meanings differ depending on LED status For alarm codes not listed here, refer to: FANUC AC Spindle Motor αi Series Maintenance Manual (B-65285EN) FANUC Spindle Alarm List (SP9001–SP9033) 1) SP9001 –... Read more...
FANUC Serial Spindle Error Codes List (01–44) – Causes & Solutions
REACO CNC is a global supplier of FANUC CNC parts, spindle amplifiers, and Mitsubishi automation components. With over 34 years of experience, we provide reliable products, professional repair services, and worldwide shipping support. This article provides a complete list of FANUC serial spindle amplifier error codes (01–44), including detailed causes and troubleshooting solutions to help engineers and maintenance personnel quickly diagnose spindle issues.  Important Notes When the yellow LED indicator on the spindle amplifier is ON, a two-digit error code is displayed. When the red LED indicator is ON, it... Read more...
FANUC CNC Troubleshooting Guide (Part 5): EX107, DC LINK & 4th Axis Setup
FANUC CNC systems are widely used in industrial automation, but users may encounter various alarms and configuration issues during operation. In this guide, we cover common FANUC CNC problems such as EX107 alarm, DC LINK voltage issues, and 4th axis configuration, along with practical solutions. With over 30 years of experience, REACO CNC provides professional support, spare parts, and repair services for FANUC CNC systems worldwide. Frequently Asked Questions (FAQ) 1. What parameters need to be modified when adding a 4th axis to FANUC 0i-MF? When adding a 4th axis, the... Read more...
FANUC CNC Troubleshooting Guide (Part 4): System Settings, Communication, and Maintenance
In addition to alarms, FANUC CNC systems may encounter issues related to system configuration, communication protocols, maintenance, and parameter settings. Proper handling of these situations is essential to ensure machine safety and performance. This guide covers practical troubleshooting topics including power modules, IO errors, PROFINET communication, and system operation precautions. 1. Where to Get FANUC Power Module Manuals? Answer To obtain detailed information about FANUC power modules, including: Alarm descriptions Wiring diagrams Dimensions Technical specifications You can refer to: Servo amplifier specification manuals System hardware connection manuals Maintenance manuals 2.... Read more...
FANUC CNC Alarm Troubleshooting Guide (Part 3): System Errors and Advanced Diagnostics
FANUC CNC systems may occasionally encounter complex alarms related to system memory, communication, servo feedback, or configuration errors. These issues often require deeper diagnostics and proper understanding of system architecture. This guide covers advanced FANUC CNC alarms and troubleshooting methods to help engineers and operators quickly identify and resolve problems. 1. How to Fix FANUC ROM Parity Error (NC Basic)? Cause ROM parity error (NC Basic) usually indicates a FROM memory failure, which may be caused by: Hardware issues Corrupted system software Solution Contact FANUC technical support Or consult REACO... Read more...
FANUC CNC Alarm Troubleshooting Guide (Part 2): Advanced Errors and Solutions
In FANUC CNC systems, some alarms are related to system configuration, program errors, or hardware failures. These alarms can be more complex and require structured troubleshooting. This guide explains additional common FANUC alarms and provides practical solutions to help reduce downtime and improve machine reliability. 1. How to Fix FANUC Alarm 5523? Cause Alarm 5523 occurs when the OPRM.INF configuration file in FROM memory is overwritten or deleted. Solution Contact FANUC technical support Or consult REACO CNC technical service Avoid modifying system files without proper authorization Related article: How to solve... Read more...
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