Start-Stop Switch
WARNING: This page is about a different car, the 2016 Lincoln MKS. However, it is still accessible from the selected car via links, so may be relevant.
The start/stop switch is a momentary contact switch that is hardwired to the RFA module, the BCM, and the PCM. When the switch is pressed, it signals the RFA module, the BCM and the PCM there is a request to either switch the ignition on or start the engine. The start/stop switch is connected to both modules as a backup in case of a failure. If there is a circuit failure to either module from the start/stop switch, the modules communicate the start/stop switch request to each other over the MS-CAN.