GMC SIERRA 2020 Owner's Manual page 254

Warning (Continued)
to use the brakes if necessary.
Select an appropriate speed while
driving in curves.
ACC may operate differently in a
sharp curve. It may reduce the
vehicle speed if the curve is too
sharp.
When following a vehicle and
entering a curve, ACC may not
detect the vehicle ahead and
accelerate to the set speed. When
this happens, the vehicle ahead
indicator will not appear.
ACC may detect a vehicle that is
not in your lane and apply the
brakes.
ACC may occasionally provide an
alert and/or braking that is
considered unnecessary. It could
respond to vehicles in different
lanes or stationary objects when
entering or exiting a curve. This is
normal operation. The vehicle does
not need service.
Driving and Operating
Other Vehicle Lane Changes
ACC will not detect a vehicle ahead
until it is completely in the lane. The
brakes may need to be manually
applied.
Objects Not Directly in Front of
Your Vehicle
The detection of objects in front of
the vehicle may not be possible if:
The vehicle or object ahead is
not within your lane.
The vehicle ahead is shifted, not
centered, or is shifted to one
side of the lane.
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