GMC TERRAIN 2018 Owner's Manual page 78

Vehicle Positioning
At times, the position of the vehicle
on the map could be inaccurate due
to one or more of the following
reasons:
The road system has changed.
The vehicle is driving on slippery
road surfaces such as sand,
gravel, or snow.
The vehicle is traveling on
winding roads or long, straight
roads.
The vehicle is approaching a tall
building or a large vehicle.
The surface streets run parallel
to a freeway.
The vehicle has been transferred
by a vehicle carrier or a ferry.
The current position calibration
is set incorrectly.
The vehicle is traveling at high
speed.
The vehicle changes directions
more than once, or the vehicle is
turning on a turn table in a
parking lot.
The vehicle is entering and/or
exiting a parking lot, garage, or a
lot with a roof.
The GPS signal is not received.
A roof carrier is installed on the
vehicle.
Tire chains are installed on the
vehicle.
The tires are replaced or worn.
The tire pressure for the tires is
incorrect.
This is the first navigation use
after the map data is updated.
The 12-volt battery has been
disconnected for several days.
The vehicle is driving in heavy
traffic where driving is at low
speeds, and the vehicle is
stopped and started repeatedly.
Navigation
Problems with Route
Guidance
Inappropriate route guidance can
occur under one or more of the
following conditions:
The turn was not made on the
road indicated.
Route guidance might not be
available when using automatic
rerouting for the next right or
left turn.
The route might not be changed
when using automatic rerouting.
There is no route guidance when
turning at an intersection.
Plural names of places might be
announced occasionally.
It could take a long time to
operate automatic rerouting
during high-speed driving.
Automatic rerouting might
display a route returning to the
set waypoint if heading for a
destination without passing
through a set waypoint.
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