Dodge 2015 Dart - Owner Manual - Manual (Page 266)

If an obstacle is detected in the center rear region, the
display will show a single solid arc in the center rear
region and will produce a one-half second tone. As the
vehicle moves closer to the obstacle, the display will
show the single arc moving closer to the vehicle and the
sound tone will change from slow, to fast, to continuous.
If an obstacle is detected in the left and/or right rear
region, the display will show a single flashing arc in the
left and/or right rear region and will produce a fast
sound tone. As the vehicle moves closer to the obstacle,
the display will show the single arc moving closer to the
vehicle and the sound tone will change from fast, to
continuous.
One-Half Second Tone
264 UNDERSTANDING THE FEATURES OF YOUR VEHICLE