FORD 2004 Expedition v.1 - Manual (Page 215)

To help avoid personal injury, please read and understand the
limitations of the reverse sensing system as contained in this
section. Reverse sensing is only an aid for some (generally large and
fixed) objects when moving in reverse on a flat surface at “parking
speeds”. Inclement weather may also affect the function of the RSS;
this may include reduced performance or a false activation.
To help avoid personal injury, always use caution when in R
(Reverse) and when using the RSS.
This system is not designed to prevent contact with small or
moving objects. The system is designed to provide a warning to
assist the driver in detecting large stationary objects to avoid damaging
the vehicle. The system may not detect smaller objects, particularly
those close to the ground.
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.
2004 Expedition (exd)
Owners Guide (post-2002-fmt)
USA English (fus)
Driving
215