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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 SP9010 Alarm 10: Input Power Voltage Low Troubleshooting
FANUC SP9010 alarm 10 means the spindle amplifier has detected low input power voltage. The main checks are the amplifier input power voltage, input power cable, CXA2A-CXA2B jumper cable, DC24V output from the common power supply module, and finally the spindle amplifier. Do not replace the spindle amplifier immediately. First confirm whether the voltage supplied to the spindle amplifier is normal and stable. If the DC24V supply is low, check the common power supply input voltage and the common power supply module before replacing the spindle amplifier. What Does FANUC SP9010... Read more...
FANUC SP9009 Alarm 09: Main Circuit Overheat and Spindle Amplifier Heat Sink Fault
FANUC SP9009 alarm 09 means the spindle amplifier main circuit temperature is too high. The alarm is usually caused by poor heat sink cooling, dirty cabinet filters, blocked airflow, external cooling fan failure, high ambient temperature, heavy cutting load, frequent spindle acceleration/deceleration, poor control board contact, or spindle amplifier failure. Before replacing the spindle amplifier, first check the cooling condition of the control cabinet, heat sink airflow, external cooling fan, air inlet filter, cutting load, and whether the alarm appears during cutting, light load, or immediately after power-on. What Does FANUC... Read more...
FANUC SP9007 Alarm 07: Spindle Motor Overspeed Troubleshooting
FANUC SP9007 alarm 07 usually means the spindle motor speed has exceeded about 115% of the maximum speed. The main checks are spindle motor parameters, spindle motor initialization, power line phase sequence, spindle detector, ladder logic during spindle synchronization, and finally the spindle amplifier. For this alarm, do not replace the spindle amplifier first. Start by checking the spindle motor model, motor code, parameter setting, and power line phase sequence. SP9007 is often related to incorrect motor parameters, wrong phase sequence, abnormal spindle detector feedback, or spindle synchronization control issues.... Read more...
FANUC SP9006 Alarm 06: Thermal Relay Disconnection and Spindle Motor Temperature Sensor Fault
FANUC SP9006 alarm 06 usually means the spindle motor temperature sensor circuit is abnormal or disconnected. The most common checks are spindle motor parameters, spindle feedback cable, motor thermistor resistance, motor insulation, ambient temperature, and finally the spindle amplifier. For this alarm, do not replace the spindle amplifier first. Start from the spindle motor parameters and feedback cable. In many cases, SP9006 is caused by incorrect motor parameter setting, damaged feedback cable, abnormal thermistor, or a temperature sensor wire disconnection. What Does FANUC SP9006 Alarm 06 Mean? FANUC SP9006 is... Read more...
FANUC SP9004 Alarm: Power Phase Loss or Fuse Blown
FANUC SP9004 Alarm: Power Phase Loss or Fuse Blown
The FANUC SP9004 alarm indicates a power phase loss or fuse blown alarm. The related amplifier alarm number is 04. This alarm occurs when the system detects an abnormal condition... Read more...
FANUC SP9003 Alarm: DC Link Fuse Blown in Spindle Amplifier
The FANUC SP9003 alarm indicates a DC link fuse blown alarm inside the spindle amplifier. The related amplifier alarm number is 03. This alarm occurs when the fuse in the DC link section of the spindle amplifier is blown or when the DC link voltage becomes insufficient due to a hardware fault. The DC link section is an important power circuit inside the spindle drive system. If the DC link fuse is blown, the spindle amplifier cannot maintain the required DC bus voltage. The CNC system may detect this condition... Read more...
FANUC SP9002 Alarm: Excessive Spindle Speed Deviation
The FANUC SP9002 alarm indicates an excessive spindle speed deviation. The related amplifier alarm number is 02. This alarm occurs when the detected spindle motor speed cannot follow the commanded spindle speed. In normal operation, the spindle motor feedback speed should closely follow the spindle command speed. If the detected speed is far away from the command speed, the CNC system may judge that the spindle cannot accelerate, decelerate, or rotate as required, and then generate the SP9002 alarm. SP9002 may be caused by excessive cutting load, unreasonable acceleration/deceleration time... Read more...
FANUC SP9001 Alarm: Spindle Motor Overheating
The FANUC SP9001 alarm indicates a spindle motor overheating alarm. The related amplifier alarm number is 01. This alarm occurs when the spindle software detects that the internal temperature of the spindle motor has exceeded the specified temperature range. When SP9001 occurs, the first step is to confirm whether the spindle motor is truly overheating or whether the temperature detection circuit is reporting an incorrect value. This can be checked by comparing the temperature shown in diagnosis No.403 with the actual motor temperature measured by an infrared thermometer or confirmed... Read more...
FANUC SV0468 Alarm: High-Speed HRV Setting Error for Amplifier
The FANUC SV0468 alarm indicates a high-speed HRV setting error for the amplifier. This alarm occurs when high-speed HRV control is enabled for an amplifier-controlled axis that does not support that HRV control level. HRV control is related to servo response and control performance. In a FANUC servo system, the available HRV level depends on the servo motor model, servo amplifier model, order specification, and supported control configuration. If the current HRV setting is higher than the capability of the installed motor or amplifier, the CNC system may generate the... Read more...
FANUC SV0466 Alarm: Motor and Amplifier Combination Mismatch
FANUC SV0466 Alarm: Motor and Amplifier Combination Mismatch
The FANUC SV0466 alarm indicates a motor and amplifier combination mismatch. This alarm occurs when the CNC system detects that the maximum current value of the servo amplifier does not... Read more...
FANUC SV0465 Alarm: Failed to Read Amplifier ID Data
The FANUC SV0465 alarm indicates that the CNC system failed to read the amplifier ID data. This alarm occurs when the system cannot read the ID information from the servo amplifier at power-on. Inside the servo amplifier, there is a data chip that stores amplifier ID information. When the CNC system is powered on, it reads this ID information to identify the connected amplifier. If the ID data cannot be read correctly, the system may generate the SV0465 alarm immediately. This alarm is usually related to poor contact of the... Read more...
FANUC SV0463 Alarm: Slave Data Transmission Error
The FANUC SV0463 alarm indicates a slave data transmission error. This alarm occurs when the servo software side cannot receive correct data because of an FSSB communication error. FSSB, also known as Fanuc Serial Servo Bus, is the communication system between the CNC control unit and the servo amplifier system. If the FSSB parameters are not set correctly, the optical fiber cable is damaged, the cable is connected incorrectly, or the amplifier control board has poor contact, the servo software may not receive valid data and the CNC system may... Read more...

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