This KB discusses the issue of why FPC is in offline state.
show chassis fpc <slot no.> detail will show the state as offline.
root@hostname> show chassis fpc 0 detail Slot 0 information: State offline
Chassisd Error log:
<timestamp> <hostname> chassisd[83147]: CHASSISD_FRU_UNRESPONSIVE: Error for FPC 0: unresponsive to attempts to start it; left it offline
"Error initializing PFE asics" log will be seen for the affected FPC.
Example of Error log:
<timestamp> <hostname> fpc0 CMT: Error initializing PFE asics
It indicates hardware failure and RMA is required for the faulty FPC.