* User Authentication Failure Errors 4001 and 2105 When Accessing ECU Upgrade

August 28, 2026 10:17 Updated

1. Symptoms

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

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

2. Cause and Solution

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