KUKA KSS01407 Error – Causes, Symptoms & How to Fix

• Error Code: KSS01407
• Category: Drive / Torque Monitoring
• Severity: High
• System: KRC4 / KSP Drives
• Impact: Affected axis stops, motion blocked, potential mechanical overload

Quick Fix for KUKA KSS01407

If the robot stops with th is error:

• Stop operation and reset the controller
• Reduce speed, acceleration, and payload
• Jog the affected axis slowly
• Check for mechanical blockage or abnormal resistance
• Restart and test under light load

Do not force the robot to move — th is can damage gearboxes or motors.

If the error disappears after reducing load, the issue is usually mechanical or payload-related, not electrical.

Typical Symptomson Site

• axis stops suddenly during motion
• Robot struggles or “jerks” before stopping
• SmartHMI shows torque error repeatedly
• Audible noise from joints or gearbox
• Motion fails under load but works when unloaded

👉 Key pattern:
“Runs fine empty → fails with payload”

What Is KUKA KSS01407?

KSS01407 is triggered when actual torque exceeds the configured safety limit.

Th is protection prevents:

• Gearbox damage
• Motor overcurrent
• Structural stresson the robot arm
• Drive overload

Once triggered, the controller disables the affected axis until the issue is resolved.

Common Symptoms

• axis stops moving unexpectedly.
• SmartHMI displays KSS01407 axis Torque Error.
• KSP drive LED may indicate a fault.
• Robot motion is jerky or blocked.
• Audible noise from gearbox or motor may be present.

Common Causes of KUKA KSS01407

1. Mechanical Obstruction or Binding

Most common in production environments.

• Foreign object blocking axis
• Misalignment in joints or couplings
• Gearbox wear or damage

2. Excessive Payload or Poor Tool Setup

• Payload exceeds robot rating
• Center of gravity not configured correctly
• Tool mounted off-axis

👉 Th is directly increases torque demand

3. Aggressive Motion Profile

• High acceleration / deceleration
• Sudden direction changes
• High-speed cycles

👉 Creates torque spikes beyond limits

4. Motor or Drive Issues

• KSP drive not regulating torque properly
• Motor winding or brake issues
• Encoder feedback errors

5. Parameter or Configuration Errors

• Torque limits set too low
• Incorrect machine data
• Firmware mismatch between KRC4 and KSP

Step-by-Step Troubleshooting for KUKA KSS01407 Error

Step 1 – Identify the axis

Check SmartHMI diagnostics
Confirm which axis triggered the torque error

Step 2 – Check Mechanical Condition

• Inspect for obstruction or collision
• Move axis manually (if safe)
• Listen for abnormal noise

Step 3 – Reduce Load and Test

• Remove payload or reduce weight
• Lower speed and acceleration
• Jog axis slowly

👉 If stable → issue is load or motion profile

Step 4 – Inspect Drive & Motor

• Check KSP drive LED status
• Inspect motor and brake function
• Verify encoder/resolver signals

Step 5 – Verify Parameters

• Check torque limits in controller
• Confirm payload and tool data
• Verify firmware compatibility

Step 6 – Replace Faulty Components

If needed:

• Servo motor
• KSP drive
• Gearbox or coupling
• Encoder/resolver cables

Recommended Replacement Parts

• KUKA KSP servo drives (KSP 600-3x20, 00-198-265)– if drive protection triggered.
• Servo motors for affected axes– check encoder/resolver integration.
• Gearboxes or couplings– if mechanical overload caused damage.
• Shielded encoder or resolver cables– prevent signal interference.

⚠️ Compatibility Tip: Confirm robot serial number, axis number, and KSS version before replacing drives or motors.

Pro Diagnostic Tip for KUKA KSS01407

• Navigate to SmartHMI → Torque Monitoring → axis Diagnostics.
• Monitor torque spikes during motion in real-time.
• Log events to identify patterns of overload.
• Compare torque readings across multiple axes.
• Persistent KSS01407 may indicate mechanical degradation or drive instability.

How to Fix KSS01407

• Remove mechanical obstruction
• Correct payload and tool data
• Reduce aggressive motion settings
• Repair or replace motor / drive
• Adjust torque parameters if misconfigured

Prevention & Maintenance

• Avoid exceeding rated payload and torque limits.
• Inspect joints, gearboxes, and couplings regularly.
• Ensure proper mounting of tools and fixtures.
• Monitor speed, acceleration, and deceleration to prevent torque spikes.
• Maintain KSP drives and servo motors in optimal condition.

Related Errors

⚠️ Technical Note: axis torque errors are often linked with:

• KSS00406Position Deviation Error– torque spikes causing axis lag.
• KSS0040Motor Error– overcurrent due to torque overload.
• KSS01404Servo Drive Error– drive protection triggered by torque spikes.
• KSS01305DC Bus Undervoltage Error– voltage drop under high torque load.

FAQ

What does KSS01407 mean?

The torqueon an axis exceeded the safe limit, so the robot stopped.

Can the robot keep running?

No. The affected axis is disabled until the issue is fixed.

What is the most common cause?

👉 Mechanical resistance or incorrect payload

Can payload misalignment trigger th is?

Yes. Incorrect center of gravity is a very common trigger.

Fastest way to fix it?

1. Reduce load
2. Check mechanical movement
3. Test at low speed
4. Inspect drive and motor