Hi,
If it is a legit hardware failure, you need a replacement but we cant tell without checking the system.
My first advice would be to backup your data asap in case you have a RAID that doesnt support failures (again.. we have no details in your description besides a "yellow LED")
I would suggest to open a TAC case to get all necessary info and then decide if it requires replacement, firmware upgrade, software reconfiguration, but a backup is imminent
-Kenny