Dodge 2009 Ram 1500 - Manual (Page 358)

Electronic Stability Program (ESP)
The ESP system enhances directional control and stability
of the vehicle under various driving conditions. ESP
corrects for oversteering or understeering of the vehicle
by applying the brake of the appropriate wheel to assist
in counteracting the oversteer or understeer condition.
Engine power may also be reduced to help the vehicle
maintain the desired path.
ESP OFF Switch
356 STARTING AND OPERATING