Ford 2006 Mountaineer Owner's Manual page 227

Certain add-on devices such as large trailer hitches, bike or
surfboard racks and any device that may block the normal
detection zone of the RSS system may create false beeps.
The RSS detects obstacles up to six
feet (two meters) from the rear
bumper with a decreased coverage
area at the outer corners of the
bumper, (refer to the figures for
approximate zone coverage areas).
As you move closer to the obstacle,
the rate of the tone increases. When
the obstacle is less than 10 inches
(25.0 cm) away, the tone will sound
continuously. If the RSS detects a
stationary or receding object further
than 10 inches (25.0 cm) from the
side of the vehicle, the tone will
sound for only three seconds. Once
the system detects an object
approaching, the tone will sound
again.
The RSS automatically turns on when the gear selector is placed in R
(Reverse) and the ignition is ON. A control in the message center allows
the driver to disable the system only when the ignition is ON and the
gear selector is in R (Reverse). Refer to Message center in the Driver
Controls chapter for more information.
Keep the RSS sensors (located on the rear bumper/fascia) free
from snow, ice and large accumulations of dirt (do not clean the
sensors with sharp objects). If the sensors are covered, it will
affect the accuracy of the RSS.
If your vehicle sustains damage to the rear bumper/fascia, leaving
it misaligned or bent, the sensing zone may be altered causing
inaccurate measurement of obstacles or false alarms.
2006 Mountaineer (mnt)
Owners Guide (post-2002-fmt)
USA (fus)
Driving
227