Saab 2008 9-3 - Manual (Page 175)

175 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:
• the system has been switched off
manually. It cannot be switched off if the
car is travelling faster than 35 mph
(60 km/h).
• there is a fault in the ABS system
• a fault has been detected and the system
has therefore been switched off and at the
same time the following message is
shown on the SID:
WARNING
When driving normally, the TCS system
helps to improve the car’s stability,
maneuverability and traction under slip-
pery road and extreme driving conditions.
The TCS must not be regarded as a
system to enable the driver to maintain
higher speeds. The same precautions
must be adopted as normal for safe cor-
nering and driving on slippery roads.
Traction control failure.
Contact service.
93_US_M08.book Page 175 Friday, May 11, 2007 11:37 AM