Starting System - Belt Integrated Starter
WARNING: This page is about a different car, the 2021 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.
The BISG is used to restart the engine during rolling starts and initial starts if conditions allow. In electric vehicle mode, when an engine start is needed BISG is commanded to crank via CAN command from the PCM. There is no torque transmitted to the driveline.