Alternator Control
WARNING: This page is about a different car, the 2010 Acura TL and 2009 Acura TL. However, it is still accessible from the selected car via links, so may be relevant.
The alternator signals the ECM/PCM during charging. The ECM/PCM then controls the voltage generated at the alternator according to the electrical load determined by the electrical load detector (ELD) and the driving mode. This reduces engine load to improve fuel economy.