Ram Trucks 2015 Chassis Cab Commercial - Diesel Supplement - Manual (Page 244)

Electronic Range Select (ERS) Operation
The Electronic Range Select (ERS) shift control allows the
driver to limit the highest available gear when the
transmission is in DRIVE. For example, if you shift the
transmission into 4 (fourth gear), the transmission will
not shift above fourth gear, but will shift through the
lower gears normally.
You can switch between DRIVE and ERS mode at any
vehicle speed. When the shift lever is in the DRIVE
position, the transmission will operate automatically,
shifting between all available gears. Tapping the ERS (-)
switch will activate ERS mode, display the current gear in
the instrument cluster, and maintain that gear as the top
available gear. Once in ERS mode, tapping the ERS (-) or
(+) switch will change the top available gear.
Column Shift Lever
242 STARTING AND OPERATING