Can not "disk replacement" by USM

hello all,

I have a EMC VNX 5100.

One of my disks is broken.

When I try to replace disk with USM, I get an error in the following steps. (when analyzing system process)

- Software revision ==> OK

- Hardware Model  ==> OK

- SP Managed      ==> OK

- Identify Replacement Candidate ==> OK

- Subsystem Faults ==> X

- Event Log ==> X

- Disk Drive Transitions ==> OK

How I can solve this problem?

Thnx