Fanuc 414 Servo Alarm Z Axis Detect Error Repack Jun 2026

If electrical testing confirms the servo drive, motor, and cables are functional, the 414 detection error is caused by severe . When the system commands a Z-axis move, the physical binding generates a massive torque spike, triggering the overcurrent or tracking loop.

| Symptom | Most Likely Culprit | | :--------------------------------------------------------------------------------------------------- | :---------------------------------------------------------------------------------------------------------------- | | Alarm appears immediately at power-up. | Power supply issue (LV alarm), shorted motor (HCA alarm), or a faulty amplifier. | | Alarm occurs only after the machine has been running for a few hours. | Overheating component (failing amplifier fan, bad motor bearings), or a feedback cable issue. | | Alarm only occurs when the Z-axis moves downward (or upward) rapidly. | Regenerative discharge circuit problem (DCA alarm), or excessive mechanical load. | | You hear a strange noise (like a "struggling" or "grinding" sound) from the motor before the alarm. | Worn motor bearings or a mechanical bind in the ballscrew. | | Swapping cables between the Z-axis and another axis moves the alarm to the other axis. | Defective cable. | | Swapping the motors between the Z-axis and another axis moves the alarm to the other axis. | Defective motor (short circuit, bad encoder, or bad winding). | fanuc 414 servo alarm z axis detect error repack

Solving FANUC 414 Servo Alarm: Z-Axis Detect Error and Repack Guidelines FANUC 414 Servo Alarm If electrical testing confirms the servo drive, motor,

| Bit | Bit Name | Description | LED Indication | |-----|----------|-------------|----------------| | #7 (bit 7) | OVL | Overload alarm | Servo amplifier LED | | | LV | Low voltage alarm → LED [2] or [3] lights | | #5 (bit 5) | OVC | Overcurrent alarm (software detection) | | #4 (bit 4) | HCA | Abnormal current alarm → LED [8] lights | | #3 (bit 3) | HVA | Overvoltage alarm → LED [1] lights | | #2 (bit 2) | DCA | Discharge (regenerative) alarm → LED [4] or [5] lights | | #1 (bit 1) | FBA | Disconnection (feedback) alarm | | #0 (bit 0) | OFA | Overflow alarm | | Power supply issue (LV alarm), shorted motor

is one of the most common, yet critical, faults encountered on CNC machines. When the screen displays "414 Servo Alarm: Z-Axis Detect Error" (or similar axis-specific messages like Y-Axis, X-Axis), it indicates that the Fanuc servo amplifier has detected an abnormal condition in the or servo drive circuit .