Buick 2009 Lucerne - Manual (Page 129)

How the System Works
LDW uses a camera located between the inside
rearview mirror and the windshield to detect the lane
markings.
@ (Lane Departure Warning): To turn LDW on and off,
press the LDW control, located by the exterior headlamp
control. An indicator on the control will light to indicate
that LDW is on.
When the vehicle is started, the LDW symbol, located in
the instrument panel cluster, will briefly come on to
indicate that the light is operational.
LDW only operates at speeds of 35 mph (56 km) or
greater. If LDW is turned on when traveling at these
speeds, the LDW symbol will appear green if the system
detects a left or right lane marking. This symbol will
change to amber and flash and three beeps will sound if
you cross a detected lane marking without using the
turn signal.
If the LDW symbol does not appear, LDW is not
currently operating and will not warn you.
To change the volume of the warning chime, see Chime
Volume under DIC Vehicle Customization on page 3-70
for more information.
When the System Does Not Seem To Work
Properly
The LDW symbol will not appear when the system is
having difficulty seeing the lines on the road or if the view
of the camera on the windshield is blocked with mud, dirt,
snow, ice, or slush, if the windshield is damaged, or when
weather limits visibility, such as while driving in fog, rain,
or snow conditions. This is normal operation, the vehicle
does not need service. For cleaning instructions, see
Washing Your Vehicle on page 5-92.
LDW warnings may occasionally occur due to tar marks,
shadows, cracks in the road, or other road imperfections.
This is normal system operation, the vehicle does not
need service.
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