Cause : DIRECTION LOCK comes when the drive is programmed to prevent a change in the motor's rotation direction. There are two main reasons for this:

1. Drive Settings: The drive might be programmed not to allow direction changes.
2. External Control Signal: An external control signal might be preventing the direction change.

The A2004 alarm code on your ABB ACS355 drive indicates a direction lock situation. This means the change of motor direction is not allowed.