Circuit/System Description
WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
The hybrid powertrain control module (HPCM) uses ignition 1 circuit terminal voltage to monitor the 12V system voltage. Ignition 1 circuit voltage also powers several of the internal drive motor generator power inverter control module (PIM) components.