User Authentication Errors 4001 and 2105 When Accessing ECU Upgrade

02 September 2026 12:33 Updated

1. Symptoms

- On some tablets, user authentication error 4001 occurs when accessing ECU Upgrade.
- When logging in again to regenerate the security certificate, user authentication error 2105 occurs even though the time and date are correct.

- User authentication error 4001 is displayed when attempting to access ECU Upgrade on multiple tablets.

2. Cause and Resolution

The issue was caused by a temporary server error. Normal operation has now been confirmed.