Circuit/System Description
WARNING: This page is about a different car, the 2010 Pontiac G5 and 2010 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
The engine control module (ECM) is supplied voltage by either the ECM/TRANS fuse, or the ECM/TCM fuse, depending on vehicle options. The ECM monitors the battery voltage to ensure that the voltage stays within the proper range. Damage to components, and incorrect data may occur if the voltage is out of range.