Kia KDS 2.0 Troubleshooting: Error Code 4001 During Login, ECU Upgrade or S/W Management

Quick links

• Applies to
• Symptom
• Cause
• Resolution
  • Step 1) Download the security certificate in the background
  • Step 2) Try a different network or mobile hotspot
  • Step 3) Remove aftermarket devices
  • Step 4) Reset vehicle power
• If the issue persists

Applies to

• Diagnostic tool: KDS 2.0
• Features: Login, ECU Upgrade, S/W Management
• Network: Wi-Fi / mobile hotspot

Symptom

Error Code 4001 appears when logging in or accessing ECU Upgrade or S/W Management.

Cause

This error may occur if the diagnostic tool does not have the required security certificate or if the certificate is outdated. This certificate is required for secure vehicle communication.

Resolution

Step 1) Trigger the background download of the security certificate

1. Log out, then fully close the diagnostic application.
2. Clear the application cache and data: Troubleshooting: Error message "4001" 
3. Restart the diagnostic tool.
4. Connect the diagnostic tool to a stable Wi-Fi network.
5. Log in again.
6. Wait a few minutes, then retry ECU Upgrade or S/W Management.

Note: The security certificate is downloaded in the background, so download progress may not be displayed on the screen.

Step 2) Try a different network or mobile hotspot

If the issue persists after completing Step 1, connect to a different network, such as a mobile hotspot. Then log in again and retry the feature.

Step 3) Remove aftermarket devices, if installed

If an aftermarket device, such as a dashcam, is installed in the vehicle, temporarily disconnect or remove it, then retry S/W Management.

Step 4) Reset vehicle power by disconnecting the negative battery terminal

Disconnect the vehicle battery negative terminal for more than 10 minutes. Reconnect the terminal, then retry the operation.

If the issue persists

• Confirm that the diagnostic tool is connected to a Wi-Fi network or mobile hotspot with internet access.
• After logging in, wait 3–5 minutes to allow the security certificate to download in the background, then retry the operation.
• If possible, test the diagnostic tool using a different network.