Alternator Control
WARNING: This page is about a different car, the 2013 Honda Fit, 2012 Honda Fit, 2011 Honda Fit, 2010 Honda Fit, and 2009 Honda Fit. 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 driving mode. This reduces engine load to improve fuel economy.