Fuel Economy Mode
WARNING: This page is about a different car, the 2008 Buick LaCrosse and 2008 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.
The BCM will enter Fuel Economy Mode when the calculated ambient air temperature is above 0°C (32°F), the calculated battery current is less than 15 amperes and greater than -8 amperes, and the battery SOC is greater than 80%. Its targeted generator output voltage is 13.0 volts. The BCM will exit this mode once the criteria are met for Charge Mode.