Jaguar XK. Service manual - part 46

187

Automatic speed limiter (ASL)

PRINCIPLE OF OPERATION

ASL can be used in a situation where
varying vehicle speed is likely but a
maximum speed must not be exceeded.

For example, where a local speed limit is
80km/h (50mph), the set speed could be
at that limit or just under. The driver is
then safe in the knowledge that the local
speed limit cannot be exceeded while
ASL is operating.

If ASL is not selected, cruise control is
always available by simply rotating the
thumb wheel on the right-hand side of the
steering wheel to set a cruising speed.
The ASL button allows the driver to select
between cruise control and the automatic
speed limiter. The ASL can be set to any
speed between 30km/h (18mph) and 240
km/h (150 mph).

When ASL is selected, the instrument
panel telltale status lamp will illuminate.
When the ASL button is pressed again,
the light will extinguish, ASL will be
cancelled and cruise control will be
available again.

USING THE ASL

Setting a speed limit

• Press the ASL button.
• Use the thumb wheel 1 to set the

required speed.

While a speed is being set or altered
the message centre display in the
instrument panel will show the
selected speed.

• The set speed can be adjusted at any

time by rotating the thumb wheel 1.

Note: The message is also displayed at
other times as an information display.

WARNING

Automatic Speed Limiter (ASL) set
speeds must be within local
speed restriction limits. The driver

must always ensure that a safe speed is
set, taking into account the prevailing
traffic and road conditions.

E94360

LIMITER SET

XXX km/h (MPH)

E91513

Automatic speed limiter (ASL)

188

When ASL is selected and a set speed
inserted, the engine will respond normally
up to the set speed. Further accelerator
pedal pressure will not increase the
vehicle speed beyond your set speed.

Suspending ASL

ASL can be suspended by pressing the
CANCEL button 3. Applying sudden,
rapid acceleration (kickdown) will also
suspend ASL.

Resuming ASL

If ASL has been suspended, it can be
reinstated with a single press of the
RESUME button 2, however, ASL will
only reinstate if the vehicle speed is less
than the current speed set in memory and
greater than 30km/h (18mph). The
message centre will display an
appropriate message if the vehicle speed
is too fast to resume ASL.

Exceeding the set speed

If the set speed is exceeded, e.g. on a
steep downhill section, the message
centre will display an appropriate
message along with an amber warning
indicator.

There are three categories of over limit
displays:
• If the set speed is exceeded by up to

15km/h (9mph), the message centre
will display the message along with
an amber warning indicator.

• If the set speed is exceeded by more

than 15km/h (9mph), the message
centre will display the message along
with a flashing amber warning
indicator.

• If the set speed is exceeded by more

than 15km/h (9mph) for a duration of
five seconds, the message centre will
display the message along with a
flashing amber warning indicator and
also give an audible warning tone.

Use your brakes to rectify the situation.

ASL unavailable

If ASL is not available due to a fault, the
message centre will display an
appropriate message along with an
amber warning indicator.

The message and warning indicator will
display continuously while ASL is
selected. When the ignition is switched
off, ASL is deactivated and any set speed
is deleted from memory.

LIMITER

CANCELLED

TOO FAST

RESUME

OVER LIMIT

XXX km/h

(MPH)

LIMITER NOT

AVAILABLE

189

Stability control

PRINCIPLE OF OPERATION

Dynamic Stability Control (DSC)

DSC is operational whenever the engine
is running, unless it has been switched
off. When the system is operating, the
warning light in the instrument panel will
flash.

The DSC system controls the Anti-lock
Braking System (ABS), traction control
and yaw control of the vehicle.

The DSC system assists the driver in
retaining directional control of the vehicle
in situations where the vehicle is sliding
(understeer or oversteer). It must not
encourage the driver to drive beyond the
limit of adhesion or at speeds higher than
those suitable for the prevailing road and
traffic conditions.

It applies braking pressure to individual
wheels if excessive variation is detected.
This ensures that the vehicle follows the
driver’s intended direction of travel.

Traction control will intervene to prevent
wheel spin by automatically reducing the
power output from the engine and
applying braking to individual wheels.
This improves acceleration, particularly
on surfaces with uneven friction, for
example, one wheel on ice the other on
tarmac.

Trac Dynamic Stability Control
(Trac DSC)

Trac DSC is an additional feature where
DSC settings are optimised for maximum
traction in difficult conditions, such as
deep snow, sand or gravel. This makes
greater traction possible, without having
to completely lose the benefits of DSC,
however, vehicle stability may be
reduced.

WARNING

The fact that the vehicle is fitted
with DSC must never allow the
driver to be tempted into taking

risks which could affect his or her safety
or that of other road users. In all cases it
remains the driver’s responsibility to
drive safely according to the prevailing
conditions.

CAUTION

Vehicle safety could be reduced by
inappropriate use of Trac DSC.
Trac DSC should only be used

when necessary for the prevailing
conditions:

In deep snow.

To maintain the movement of the vehicle
on soft or loose surfaces e.g. gravel,
sand.

When snow chains are fitted.

Stability control

190

USING STABILITY CONTROL

Switching between DSC and Trac
DSC

• Press and hold the DSC switch for

less than 10 seconds.

• The message centre will temporarily

display either Trac DSC or DSC ON.

• The indicator lamp on the instrument

panel will illuminate while Trac DSC is
selected.

• The indicator lamp will flash when

DSC or Trac DSC is active.

Note: If cruise control is engaged it will
automatically disengage if stability control
activates.

Switching between DSC OFF and
ON

Switching DSC OFF:
• Press and hold the DSC switch for

more than 10 seconds.

• The message centre will temporarily

display DSC OFF and a short warning
chime will sound.

• The indicator lamp on the instrument

panel will illuminate.

Switching DSC ON:

If DSC is OFF:
• Press and release the DSC switch.
• The DSC system will switch on, the

message centre will temporarily
display DSC ON.

• The indicator lamp on the instrument

panel will be extinguished.

Stability control indicator

When Dynamic Stability
Control (DSC) is Off, the
indicator lamp will illuminate

and a chime will sound. When tracDSC or
DSC is active the indicator lamp will flash.
If there is a fault the indicator lamp will
illuminate and the message centre will
display DSC NOT AVAILABLE.

It is safe to drive the vehicle but the DSC
system will not activate under wheel spin
or slide conditions. You should seek
qualified assistance as soon as possible.

Computer Active Technology
System (CATS)

If the message centre displays the
message CATS SYSTEM FAULT, a fault
has been detected in the adaptive
damping system. Seek qualified
assistance as soon as possible.

E91525

Content .. 44 45 46 47 ..