The fault AuE2 in Delta MS300 drive indicates an Auto-tune error 2. This means auto-tuning process failed due to motor phase loss error occur when drive run autotune function.

Auto-tuning is a process where the drive automatically adjusts its internal parameters to optimize performance for the specific motor connected to it.

1. Check motor wiring.
2. Verify that the three-phases of the electromagnetic valve are all closed.
3. Check if the wires are broken.