Jeep 2010 Liberty - Manual (Page 169)

The system will indicate a detected obstacle by showing
three solid arcs and will produce a
1 ⁄
2
second tone. As the
vehicle moves closer to the object the EVIC display will
show fewer arcs and the sound tone will change from
slow, to fast, to continuous.
Rear Park Assist Disabled Slow Tone
168 UNDERSTANDING THE FEATURES OF YOUR VEHICLE