L322 Range Rover System Description and Operation
BRAKES
DESCRIPTION AND OPERATION
70-27
If the power supply has been interrupted by disconnecting the vehicle's battery, ABS and DSC will be deactivated.
These functions are reactivated by driving a short distance, or by turning the steering wheel from lock to lock while
the vehicle is stationary and the engine is running. Reactivation is indicated by extinguishing of the warning lamps.
ETC is continuously available to boost vehicle traction when one or more wheels has a tendency to spin. It operates
in conjunction with the DSC system. If a wheel is tending to spin, ETC automatically brakes that wheel until it regains
grip and can transmit the engine's power again. This braking activity causes the engine's power to be transferred to
the remaining wheels. Some noise may be generated when the brake is applied to the spinning wheel.
It is possible to de-select the stability control function of DSC, leaving the ETC system active, by pressing the DSC
button. The amber DSC lamp illuminates continuously, to indicate that the stability function is passive. It is
recommended that the DSC system should be temporarily de-selected, in order to maximise forward traction, only in
the following exceptional circumstances:
l
If the vehicle needs to be rocked out of a hollow or a soft surface
l
Starting in deep snow, or on a loose surface
l
Driving in deep sand
l
On tracks with deep longitudinal ruts
l
Driving through deep mud.
If the DSC button is pressed a second time, the system will be re-selected, and the amber DSC lamp will extinguish.
Electronic Traction Control (ETC)
The ability to control the vehicle while driving, is lost as a result of excessive wheel spin or slip if a tyre exceeds its
ability to:
l
Maintain traction
l
Accept side forces to maintain directional control
The ETC feature of the DSC on the New Range Rover cannot be switched OFF with the DSC switch. Pressing the
button will only switch off the dynamic stability control function of the DSC.
The traction control feature is needed at all times to provide anti-wheel spin control especially when driving the vehicle
off road. The DSC warning lamp in the instrument cluster will come on when the system is switched off manually or
there is a fault in the system.
Off road traction control or HDC operation places an additional load on the brakes. To prevent overheating of the
brakes and discs, the temperature of the discs is calculated over time from the road speed and amount of brake
application (from the pressure sensor). If the temperature of one or more discs goes above approximately 600
°
C, the
traction control function for that wheel will be cancelled temporarily. Engine intervention is still active to prevent
spinning of that wheel. Once the temperature of the disc goes below approximately 500
°
C, the traction application will
be reactivated.
The normal braking function (including ABS) is always active at any temperatures.
Corner Braking Control (CBC)
CBC improves stability control while braking through corners.
As the vehicle enters a corner, the weight of the vehicle shifts to the outside wheels. With non CBC equipped vehicles,
if the driver brakes while driving through a corner an equal hydraulic force is applied to each wheel. Though the
pressure is equal the grip available for braking is unequal at the tyre footprint due to the increased weight on the
outside wheels.
With a CBC equipped vehicle, the feature regulates the applied pressure to the wheels based on the rate of cornering.
When the driver brakes, an unequal hydraulic pressure is applied to each side of the vehicle. Though the brake
application pressure to each wheel is unequal, the dynamic of the vehicles weight transfer compensates for the
unequal pressure, as a result braking effort is distributed in proportion to the grip available ensuring that lateral grip
is maintained.