Intelligent technology
148Anti-lock brake system and traction control
ABSAnti-lock brake system (ABS)
The anti-lock brake system prevents the wheels locking
during braking.The anti-lock brake system (ABS) is an important part of the vehicle’s active
safety system.
How the ABS works
If one of the wheels is turns too slowly in relation to the road speed, and is
close to locking, the system will reduce the braking pressure for this wheel.
The driver is made aware of this control process by a pulsating of the brake
pedal and audible noise. This is a deliberate warning to the driver that one or
more of the wheels is tending to lock and the ABS control function has inter-
vened. In this situation it is important to keep the brake pedal fully depressed
so the ABS can regulate the brake application. Do not “pump”.
If you brake hard on a slippery road surface, the best possible control is
retained as the wheels do not lock.
However, ABS will not necessarily guarantee shorter braking distances in all
conditions. The braking distance could even be longer if you brake on gravel
or on fresh snow covering a slippery surface.
WARNING
•
The anti-lock brake system cannot defy the laws of physics. Slippery
and wet roads are dangerous even with ABS! If you notice that the ABS is
working (to counteract locked wheels under braking), you should reduce
speed immediately to suit the road and traffic conditions. Do not let the
extra safety features tempt you into taking any risks when driving.
•
The effectiveness of ABS is also determined by the tyres fitted
⇒ page 196.
•
If the running gear or brakes are mo dified, the effectiveness of the ABS
could be severely limited.
Traction control system (TCS)*
The traction control system prevents the drive wheels from
spinning when the car is acce lerating. The system always
includes ABSDescription and operation of the traction control system during acceleration
(TCS)
TCS reduces engine power to help prevent the drive wheels of front-wheel
drive vehicles losing traction during acceleration. The system works in the
entire speed range in conjunction with ABS. If a malfunction should occur in
the ABS, the TCS will also be out of action.
TCS helps the vehicle to start moving, accelerate and climb a gradient in slip-
pery conditions where this may otherwise be difficult or even impossible.
The TCS is switched on automatically when the engine is started. If necessary,
it may be turned on or off pushing the button on the centre console.
When the TCS is off, the warning lamp is lit. The TCS should normally be left
switched on at all times. Only in exceptional circumstances, when slipping of
the wheels is required, should it be disconnected, for example•
With compact temporary spare wheel.
•
When using the snow chains.
•
When driving in deep snow or on loose surfaces.
•
When the vehicle is bogged-down, to free it by “rocking.”WARNING (continued)
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