GMC Sierra Denali 2017 Owner's Manual page 290

pressing SET will result in cruise
control set to the current vehicle
speed.
Using Cruise Control on Hills
How well the cruise control works
on hills depends on the vehicle
speed, the load, and the steepness
of the hills. When going up steep
hills, pressing the accelerator pedal
may be necessary to maintain
vehicle speed.
While going downhill:
Vehicles with a 6-speed
automatic transmission and a
gasoline engine have Cruise
Grade Braking to help maintain
driver selected speed.
Cruise Grade Braking is enabled
when the vehicle is started and
cruise control is active. It is not
enabled in Range Selection
Mode. It assists in maintaining
driver selected speed when
driving on downhill grades by
using the engine and
transmission to slow the vehicle.
To disable and enable Cruise
Grade Braking for the current
ignition key cycle, press and
hold the Tow/Haul button for
five seconds. A DIC message
displays. See Transmission
Messages 0 152.
Vehicles with a diesel engine
have Cruise Grade Braking
enabled when Tow/Haul Mode is
on, the exhaust brake is on,
or both are on.
For other forms of descent control,
see Hill Descent Control (HDC)
0 286,Automatic Transmission
0 267, and Tow/Haul Mode 0 273.
Ending Cruise Control
There are four ways to end cruise
control:
Step lightly on the brake pedal.
Press .
Shift the transmission to
N (Neutral).
To turn off cruise control,
press .
Driving and Operating
Erasing Speed Memory
The cruise control set speed is
erased from memory if
or the ignition is turned off.
289
is pressed