Circuit/System Description
WARNING: This page is about a different car, the 2008 GMC Yukon and 2008 Chevrolet Tahoe. However, it is still accessible from the selected car via links, so may be relevant.
The hybrid powertrain control module (HPCM) continuously monitors the system voltage on the Ignition voltage circuits. The HPCM is located within the drive motor generator power inverter module (PIM) assembly and is not serviced separately. Higher than normal voltage may cause the control module or sensors to operate improperly.