Dodge Challenger 2012 Owner's Manual page 204

202 UNDERSTANDING YOUR INSTRUMENT PANEL
The FUEL SAVER MODE message will display above the
average fuel economy in the EVIC display. This message
will appear whenever the Multi-Displacement System
(MDS) (if equipped) allows the engine to operate on four
cylinders, or if you are driving in a fuel efficient manner.
Fuel Saver Mode — On
This feature allows you to monitor when you are driving
in a fuel efficient manner, and it can be used to modify
driving habits in order to increase fuel economy.
Fuel Saver Mode — Off