Ford Expedition 2009 Owner's Manual page 760

AIR SUSPENSION SYSTEM (IF EQUIPPED)
The air suspension system is designed to improve ride, handling and
general vehicle performance during:
• Certain road conditions
• Steering maneuvers
• Braking
• Acceleration
This system keeps the rear of your vehicle at a constant level by
automatically adding air or releasing air from the springs. If you exceed
the load limit, the rear air suspension may not operate. The air
suspension system will stay active for 40 minutes after the ignition is
turned off to accommodate any load changes. (The air compressor may
run when the vehicle is off; this is normal.)
The air suspension system can be enabled or disabled through the
message center. Refer to Message center in the Driver Controls chapter.
If the system is off, the rear air suspension will not operate and will not
raise (pump) or lower (vent) while the vehicle is not moving. However, if
the system determines that the vehicle is low or high and needs to make
a height adjustment while driving at speeds above 15 mph (24 km/h), the
system will pump or vent as required. Normal vehicle operation does not
require any action by the driver.
WARNING: On vehicles equipped with air suspension, turn the
air suspension and the ignition switch off prior to jacking,
hoisting or towing your vehicle.
LIMITED-SLIP AXLE (IF EQUIPPED)
This axle provides added traction on slippery surfaces, particularly when
one wheel is on a poor traction surface. Under normal conditions, the
limited slip axle functions like a standard rear axle.
Extended use of other than the manufacturer's specified size tires on a
limited slip rear axle could result in a permanent reduction in
effectiveness. This loss of effectiveness does not affect normal driving
and should not be noticeable to the driver.
PREPARING TO DRIVE
WARNING: Utility vehicles have a significantly higher rollover
rate than other types of vehicles.
2009 Expedition (exd)
Owners Guide, 2nd Printing
USA (fus)
Driving
297