  That is normal. When the CMC is removed or fails over all fans will run at maximum RPM until the CMC comes back online. If the errors still persist then test each CMC by itself. Remove both CMCs and then insert 1 CMC. If they work by themselves then check the firmware revision of each one when they are inserted. If the firmware is different then perform updates to get them on the same revision. 
HI,  i'm getting an error in Dell M1000e Blade Enclosure as below . " Critical CMC 1 Degraded Microcontroller Senser for CMC. Redundancy lost was asserted.   appreciate if anybody could explain me what will be the issue with above warning   Thanks in advance, Nishantha.
Dell PE M1000e Blade Enclosure