Lincoln 2013 MKZ Owner's Manual page 209

If a message regarding a blocked
sensor appears in the information
display, the radar signals from the
sensor have been obstructed. The
sensors are located behind a fascia
cover near the driver side of the lower
grille. When the sensors are
obstructed, a vehicle ahead cannot
be detected and the collision warning
system does not function. The
following table lists possible causes
and actions for this message being
displayed.
Cause
The surface of the radar in the grille is
dirty or obstructed in some way
The surface of the radar in the grille is
clean but the message remains in the
display
Heavy rain, spray, snow, or fog is inter-
fering with the radar signals
Swirling water, or snow or ice on the
surface of the road may interfere with
the radar signals
Driving Aids
Clean the grille surface in front of the
radar or remove the object causing the
Wait a short time. It may take several
minutes for the radar to detect that it
The collision warning system is
temporarily disabled. Collision warning
should automatically reactivate a
short time after the weather conditions
The collision warning system is
temporarily disabled. Collision warning
should automatically reactivate a
short time after the weather conditions
206
Action
obstruction
is no longer obstructed
improve
improve