Jaguar XJ (X350). Manual - part 239
temperature limit. The traction control brake intervention will remain disabled until the brakes have
cooled, irrespective of ignition switch position or ignition switch cycling.
Stability Assist
Dynamic stability control (DSC) maximizes vehicle stability under all conditions. The DSC system
compares actual vehicle course to that intended by the driver. If the intended course differs from the
actual course due to over steer or under steer conditions, the DSC system will brake individual
wheels and reduce engine torque to bring the vehicle back to the driver's intended direction. By
using a combined yaw rate sensor and lateral accelerometer, the vehicles rotational motion around
its vertical axis and centrifugal forces generated while cornering are calculated to determine the
vehicle's actual behavior. Using additional sensors for detecting steering wheel position and road
wheel speed enables the system to recognize the driver's intentions.
Dynamic stability control is enabled/disabled via the DSC ON/OFF switch. When the switch is in the
OFF position, the amber DSC warning lamp solidly illuminates within the instrument cluster message
center. The DSC is automatically activated when the ignition is switched on. The DSC also provides
failure messages via the instrument cluster message center.
Emergency Brake Assist
The emergency brake assist function allows the driver to enter ABS with greater speed and efficiency
so that maximum braking is achieved sooner. Using the information received from the wheel speed
sensors, brake pedal travel switch, master cylinder pressure transducer, master cylinder active
booster solenoid and the yaw rate sensor and accelerometer, the ABS module detects whether more
braking pressure can be applied in relation to how much braking pressure the driver is applying in an
emergency braking situation.
Inspection and Verification
1 . Verify the customer concern.
2 . Confirm if the ABS warning light was illuminated, or still is.
NOTE:
An intermittent fault may allow the warning light to go off. This does not necessarily mean the
fault is not present. Some warnings will appear to clear when the ignition is cycled. This is often
because the warning has flagged as a result of one of the vehicle's on-board diagnostic routines
having run to detect the fault. If the same routine is not run when the ignition is switched ON,
the warning will not reflag until the routine does run.
3 . Visually inspect for obvious signs of mechanical or electrical damage.
Mechanical
Electrical
•
Brake fluid level
•
Vacuum system
•
Warning light operation
•
Fuses (see table)