GMC Yukon 2007 Owner's Manual page 155

You can choose among five driving settings:
Indicator lights in the switches show you which
setting you are in. The indicator lights will come on
briefly when you turn on the ignition and the last
chosen setting will stay on. If the lights do not
come on, you should take your vehicle in for
service. An indicator light will flash while shifting.
Fast flashing means the conditions were not
met to make the desired shift, typically the vehicle
was going too fast, the automatic transmission
was not in neutral or the clutch pedal was not fully
pressed. Slow flashing means the shift is in
progress. It will stay on when the shift is
completed. If for some reason the transfer case
cannot make a requested shift, it will return to the
last chosen setting.
m
2 (Two-Wheel Drive High): This setting is
used for driving in most street and highway
situations. Your front axle is not engaged in
two-wheel drive. This setting also provides the
best fuel economy.
AUTO (Automatic Four-Wheel Drive): This
setting is ideal for use when road surface traction
conditions are variable. When driving your
vehicle in AUTO, the front axle is engaged, but
the vehicle's power is primarily sent to the
rear wheels. When the vehicle's software
determines a need for more traction, the system
will transfer more power to the front wheels.
Driving in this mode results in slightly lower fuel
economy than Two-Wheel Drive High.
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4 (Four-Wheel Drive High): Use the
four-wheel high position when you need extra
traction, such as on snowy or icy roads or in most
off-road situations. This setting also engages
your front axle to help drive your vehicle. This is
the best setting to use when plowing snow.
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4 (Four-Wheel Drive Low): This setting also
engages your front axle and delivers extra torque.
You may never need this setting. It sends maximum
power to all four wheels. You might choose
Four-Wheel Drive Low if you are driving off-road in
deep sand, deep mud, deep snow, and while
climbing or descending steep hills. StabiliTrak
not engage in this mode. See StabiliTrak
on page 367 for more information.
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