Circuit/System Description
WARNING: This page is about a different car, the 2016 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
The stop/start capacitor is switched in series to the standard battery by the stop/start capacitor control module during engine restarts to boost voltage. The stop/start capacitor control module monitors the state of the stop/start capacitor and communicates to the ECM.