Ford Town Car 2009 Owner's Manual page 191

Distance to Object
Speed above 2.5 mph (4 km/h)
up to 1.6 feet (.5 meters)
1.6 feet (.5 meters) to 3.1 feet
(1 meter)
3.1 feet (1 meter) to 5.7 feet
(1.8 meters)
5.7 feet (1.8 meters) to 9 feet
(2.8 meters)
9 feet (2.8 meters) to 13 feet
(4 meters)
13 feet (4 meters) to 19.6 feet
(6 meters)
Speed below 2.5 mph (4 km/h)
up to 1.4 feet (.4 meters)
1.4 feet (.4 meters) to 3 feet
(.9 meters)
3 feet (.9 meters) to 4.5 feet
(1.4 meters)
4.5 feet (1.4 meters) to
6.3 feet (1.9 meters)
6.3 feet (1.9 meters) to
8.7 feet (2.6 meters)
8.7 feet (2.6 meters) to
16.4 feet (5 meters)
The reverse sensing system is automatically enabled 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.
The message center will indicate the system is off and will not allow the
driver to switch the system on to indicate a failure of the reverse sensing
system.
2009 Town Car (tow)
Owners Guide, 1st Printing
USA (fus)
Audible Warnings
Warning
Solid
Fast beep
Medium/fast beep
Medium beep
Medium/slow beep
Slow beep
Solid
Fast beep
Medium beep
Medium/slow beep
Slow beep
No sound
Driving
191