Is there a way to reboot 3G/4G LTE Cellular modem without rebooting the router?

NOTE: the command “test cellular <interface> modem-power cycle” is a hidden command. You must configure first “service internal” before the command can be used.

You will lose connectivity to the cli for a brief moment while power cycling.

Router(config)#service internal
Router(config)#exit
Router#test cellular 0 modem-power-cycle
Modem Power cycled successfully
Router#