BMW 740I Owner's Manual page 186

ATC
In order to take driving conditions into
account, ATC registers corners and
both uphill and downhill gradients. For
example, if you maintain speed through
a curve, the transmission does not up-
shift.
On uphill gradients, it shifts only when
the engine speed increases in order to
make more efficient use of power re-
serves. On downhill gradients ATC
downshifts when the speed of the vehi-
cles increases causing the driver to
step on the brakes.
With respect to road conditions, ATC
monitors the friction between the tires
and the road. The system responds to
slippery road surfaces (snow and ice)
by activating the winter program.
Second gear is used when moving
away from a standstill, upshifts occur
sooner, and on descents downshifting
does not occur in spite of the applica-
tion of brakes. This enables you to
"feel" the road as you drive and pro-
duces greater dynamic stability. If the
friction between the tires and the road
is adequate, the normal system is again
activated. The system also leaves the
winter program when you shift from
drive position "D" to "S," "3" or "2," or if
*
the ASC+T/DSC is deactivated.
By recognizing traffic conditions, ATC
can retain maximum driving comfort.
For instance, the system recognizes
stop-and-go traffic and then proceeds
only in second gear until it encounters
higher starting loads.
Of course the selector lever can still be
used to select specific gear ratios. Per-
formance-oriented driving is enabled by
shifting from drive position "D" to "S,"
"3" or "2." Positions "3" and "2" each
limit upshifts to the next gear. Position
"2" is best for driving on steep mountain
slopes with a heavy load.
ASC+T/DSC
*
Precision sensors monitor the number
of revolutions of the wheels. When
equipped with DSC, they also monitor
steering angle, lateral acceleration,
brake pressure and the movement of
the vehicle around its vertical axis.
If differences in the wheel speeds oc-
cur, the system counteracts the danger
of wheelspin by reducing torque. If nec-
essary, the system also responds with
additional applications of the brakes at
the rear wheels.
If the system detects an instability in the
vehicle's condition, the braking action
can also be directed to the front wheels
by the DSC in order to stabilize the ve-
hicle.
You may need some time to become
accustomed to this system intervention.
However, it helps provide optimum pro-
pulsive force and driving stability.
The braking intervention may be ac-
companied by a certain degree of
noise.
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