2011 Cadillac DTS Owner's Manual - Page 146

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. 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 4 ‑ 74 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 6 ‑ 98 . 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. 3-44 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.