GMC SIERRA 2020 Owner's Manual page 255

254 Driving and Operating
Driving in Narrow Lanes
Vehicles in adjacent traffic lanes or
roadside objects may be incorrectly
detected when located along the
roadway.
Do Not Use ACC on Hills and
When Towing a Trailer
Do not use ACC when driving on
steep hills or when towing a trailer.
ACC will not detect a vehicle in the
lane while driving on steep hills.
If the brakes are applied, ACC
disengages.
Disengaging ACC
There are three ways to
disengage ACC:
Step lightly on the brake pedal.
Press .
Press .
Erasing Speed Memory
The ACC set speed is erased from
memory if is pressed or if the
ignition is turned off.
Weather Conditions Affecting ACC
If the interior temperature is
extremely high, the instrument
cluster may indicate that ACC is
temporarily unavailable. This can be
caused by extreme hot weather
conditions with direct sunlight on the
front camera. ACC will return to
normal operation once the cabin
temperature is lower.
Conditions that are associated with
low visibility, such as fog, rain,
snow, or road spray, may limit ACC
performance. Water droplets from
rain or snow that remain on the
windshield may also limit ACC s
ability to detect objects.
Lighting Conditions Affecting ACC
The ACC front camera can be
affected by poor lighting conditions,
and ACC may have limited
performance when:
There are changes in brightness,
such as entering and exiting
tunnels, bridges, and
overpasses.
Low sun angles cause the
camera to not detect objects,
or it is more difficult to detect
objects in the same traffic lane.
Lighting is poor in the evening or
early morning
There are multiple changes in
brightness or shadows along the
vehicle roadway.
In a tunnel without the
headlamps on, or in a tunnel
when there is a vehicle in front
that does not have its
taillamps on.