EL
ErrorLib
Brands
||
  1. Home
  2. Fanuc
  3. Alpha i Series AC Servo Motor and Spindle
  4. 5
About·Privacy·Terms

ErrorLib — Industrial Fault Code Library

Disclaimer: ErrorLib is an independent technical reference tool. While we aim for accuracy, always verify with the manufacturer’s official service manuals before performing maintenance on industrial equipment. ErrorLib is not affiliated with the brands listed.

5

Low-voltage of Control Power Supply (ECM)

Fanuc · Alpha i Series AC Servo Motor and Spindle

What does 5 mean?

The 24V control power supply voltage to the ECM has dropped below the acceptable threshold. This can lead to improper operation or shutdown of the ECM.

Common Causes

  • The control power supply voltage (e.g., 24VDC) is below the minimum operational threshold.
  • Power supply unit failure or overload.
  • Loose wiring or poor connection to the control power input.
  • External short circuit on the control power lines.
  • Battery for control power is depleted or faulty.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Measure the 24V control power supply voltage at the input terminals to the ECM.

  2. 2

    Check the external 24V power supply unit for proper operation and load capacity.

  3. 3

    Inspect the wiring from the 24V power supply to the ECM for voltage drops or loose connections.

Browse all codes in this manual (29)
Verified technical data. Last updated: April 2026

Related Faults

08Regeneration Excess Alarm1Over-current at Power Running (ECM)2Over-current at Regeneration (ECM)
Source: Fanuc Alpha i Series AC Servo Motor and Spindle
Open Manual (Page 588)Search more codes in this manual