Battery Save Mode
WARNING: This page is about a different car, the 2005 Dodge Viper. However, it is still accessible from the selected car via links, so may be relevant.
The BCM has a battery save mode. This provides the customer with the ability to conserve battery power when storing the vehicle for up to three months without losing radio and Powertrain Control Module (PCM) memory. This is an alternative to disconnecting the battery negative cable.