A monitor and control system and a method of monitoring and controlling an onboard system of an assembly includes one or more of a plurality of sensors detects whether an event occurred in the onboard system. The sensors communicate with a master controller when the master controller is in a nominal mode in which the master controller is powered on to actively monitor the sensors, and includes a sleep mode in which the master controller is powered off and does not monitor the sensors when in the sleep mode. An agent controller monitors the sensors when the master controller is in the sleep mode. One or more of the sensors signal the agent controller that the event has occurred. The agent controller signals the master controller to awaken from the sleep mode in response to the one or more of the sensors signaling the agent controller of the event.