Saab 2007 9-3 - Manual (Page 173)

173 Starting and driving
Traction Control
System (TCS)
Anti-spin system
How the system works
The Traction Control System (TCS) is
designed to prevent wheelspin. This
enables the car to achieve the best possible
grip and, hence, maximum tractive effort,
together with greater stability.
The TCS uses information from the ABS
wheel sensors to detect when the front (driv-
ing) wheels are rotating faster then the rear
wheels.
If the two front wheels are rotating faster
than the rear wheels, the torque from the
engine is reduced to eliminate the differ-
ence.
The process continues until all the wheels
are rotating at the same speed.
The advantages of the TCS become most
apparent when the cohesion between the
front wheels and the road surface is so low
that one or both of the wheels would lose
their grip were the car not equipped with the
TCS, e.g.:
• When the car is pulling away or accelerat-
ing with the front wheels on different
surfaces (e.g. one slippery and one dry),
the TCS functions like an electronic differ-
ential lock, making sure that both wheels
rotate at the same speed. The system
also functions when the car is reversing.
• When cornering, if the inside front wheel
rotates faster than the other wheels.
TCS OFF
lights up if:
• a fault has been detected and the system
has therefore been switched off
• there is a fault in the ABS system
• the system has been switched off
manually.
WARNING
When driving normally, the TCS system
helps to improve the car’s directional
stability. The TCS must not be regarded
as a system to enable the driver to main-
tain higher speeds. The same precau-
tions must be adopted as normal for safe
cornering and driving on slippery roads.
93_U S_M 07.book Page 173 W ednesday, A pril 12, 2006 9:30 A M