Ford Expedition 2009 Owner's Manual page 773

Driving
Positions of the Control Trac system
The Control Trac system functions
in four modes:
• 2H (2WD) delivers power to the
rear wheels only. This is
appropriate for normal on-road
driving on dry pavement and
provides best fuel economy.
• 4A (4X4 AUTO) provides
electronic control four-wheel
drive with power delivered to all
four wheels, as required, for increased traction. The RTT location in
the message center will display "4X4 AUTO" when this position is
selected. This mode is acceptable for all on-road driving but
recommended when wet pavement, snow, or loose gravel conditions
are expected.
• 4H (4X4) provides electronically locked four-wheel drive power to
front and rear wheels. The RTT location in the message center will
display "4X4" when this position is selected. This position is not
recommended for use on dry pavement. This position is only intended
for severe winter or off-road conditions, such as deep snow, ice or
shallow sand.
• 4L (4X4 LOW) provides electronically locked four-wheel drive when
extra power at reduced speeds is required. The RTT location in the
message center will display "4X4 LOW" when this position is selected.
This position is not recommended for use on dry pavement. Use this
position for off-road low-speed operation or when extra power is
required, such as climbing steep grades, going through deep sand or
pulling a boat out of the water.
Note: If your vehicle is equipped with AdvanceTrac with RSC, the
AdvanceTrac with RSC system will automatically turn off the stability
enhancement feature when you shift the Control Trac four-wheel drive
system into 4L (4X4 LOW). The brake traction enhancement feature will
still be enabled.
The AdvanceTrac with RSC stability enhancement system can be turned
off manually by pressing the AdvanceTrac with RSC button (refer to
AdvanceTrac with Roll Stability Control™ (RSC) Stability
Enhancement System in this chapter) while operating in 2H, 4A or 4H
while driving in deep sand, very deep snow or more strenuous off-road
maneuvers. This will disable the engine management feature, allowing
the vehicle to maintain full power and enhanced momentum through the
obstacle.
310
2009 Expedition (exd)
Owners Guide, 2nd Printing
USA (fus)