Arul is correct and in fact if the command is available to shut the service module you should do so before removing the module or reloading the switch.
Not all service modules need shutting down. Basically if you type
hw-module module
the CLI will only give you the further option of "shutdown" if the service module supports it eg.
An FWSM does support shutdown so you would get the option in the above command
A CSM does not support shutdown so you would only get the option to reload.
Jon
