Published: 11-May-2011
Wheels and Tires - Wheels and Tires - System Operation and Component Description
Description and Operation
Control Diagram
NOTE: A = Hardwired; F = RF Transmission; N = Medium speed CAN bus; W = LF Transmission
Item Description 1 Battery 2 Megafuse (250A) 3 CJB (central junction box) 4 RJB (rear junction box) 5 TPMS receiver 6 Tire pressure sensors
7 Initiators 8 TPMS module 9 Instrument cluster
Tire Pressure Monitoring System (TPMS) System Operation
The controlling software for the Tire Pressure Monitoring System (TPMS) is located within a Tire Pressure Monitoring System
Module. The software detects the following:
When the tire pressure is below the recommended low pressure value - under inflated tire.
The location of the tire on the vehicle that is below the recommended pressure.
Malfunction warning.
The TPMS system comprises:
Tire pressure monitoring system module located below the right-hand front seat.
Tire pressure receiver located near the gear shifter within the floor console.
Two front initiators positioned forward of the wheels and behind the fender splash shields.
Two rear initiators positioned rearward of the wheels and assembled on dedicated brackets located behind the fender
splash shields.
Four sensors, each sensor is integral with a tire valve and located within the tire; the space saver spare wheel is not
fitted with a sensor.
The four initiators are hard wired to the TPMS module. The initiators transmit 125 KHz Low Frequency (LF) signals to the tire
pressure sensors which respond by modifying the mode status within the Radio Frequency (RF) transmission. The 315 or 433
MHz RF signals are detected by the tire pressure receiver which is connected directly to the TPMS module. The received RF
signals from the tire pressure sensors are passed to the TPMS module and contain identification, pressure, temperature and
acceleration information for each wheel and tire.
The TPMS module communicates with the instrument cluster via the medium speed CAN bus to provide the driver with
appropriate warnings. The TPMS module also indicates status or failure of the TPMS or components.
Tire Location and Identification
The TPMS can identify the position of the wheels on the vehicle and assign a received tire pressure sensor identification to a
specific position on the vehicle, for example front left, front right, rear left and rear right. This feature is required because of
the different pressure targets and threshold that could exist between the front and rear tires.
The wheel location is performed automatically by the TPMS module using an 'auto-location' function. This function is fully
automatic and requires no input from the driver. The TPMS module automatically re-learns the position of the wheels on the
vehicle if the tire pressure sensors are replaced or the wheel positions on the vehicle are changed.
The TPMS software can automatically detect, under all operating conditions, the following:
one or more new tire pressure sensors have been fitted
one or more tire pressure sensors have stopped transmitting
TPMS module can reject identifications from tire pressure sensors which do not belong to the vehicle
two 'running' wheels on the vehicle have changed positions.
If a new tire pressure sensor is fitted on any 'running' wheel, the module can learn the new sensor identification automatically
through the tire learn and location process.
The tire-learn and location process is ready to commence when the vehicle has been stationary or traveling at less than 12
mph (20 km/h) for 15 minutes. This is known as 'parking mode'. The learn/locate process requires the vehicle to be driven at
speeds of more than 12 mph (20 km/h) for 15 minutes. If the vehicle speed reduces to below 12 mph (20 km/h), the learn
process timer is suspended until the vehicle speed increases to more than 12 mph (20 km/h), after which time the timer is
resumed. If the vehicle speed remains below 12 mph (20 km/h) for more than 15 minutes, the timer is set to zero and process
starts again.
Low Pressure Monitoring
The tire low pressure sensor transmits by RF (315 MHz or 433 MHz depending on market) signal. These signals contain data
which corresponds to tire low pressure sensor identification, tire pressure, tire temperature, acceleration and tire low pressure
sensor mode.
Each time the vehicle is driven, the tire pressure monitoring system module activates each LF antenna in turn. The
corresponding tire low pressure sensor detects the LF signal and responds by modifying the mode status within the RF
transmission.
The system enters 'parking mode' after the vehicle speed has been less than 20 km/h (12.5 miles/h) for 12 minutes. In parking
mode the tire low pressure sensors transmit a coded signal to the tire pressure monitoring system module once every 13
hours. If the tire pressure decreases by more than 0.06 bar (1 lbf/in²) the tire low pressure sensor will transmit more often as
pressure is lost.
As each wheel responds to the LF signal from the tire pressure monitoring system module, it is assigned a position on the
vehicle and is monitored for the remainder of that drive cycle in that position.
The TPMS uses active tire pressure sensors which are located on each wheel, inside the tire cavity. The sensor incorporates the
tire valve and is secured in the wheel by a nut on the outside of the wheel. The sensor contains a Printed Circuit Board which
houses a PTC (positive temperature coefficient)sensor, a Piezo pressure sensor, a radio receiver and transmitter and a lithium
battery.
The tire pressure sensors use the PTC sensor and the Piezo sensor to periodically measure the pressure and temperature of
the air inside the tire. The data is transmitted by RF data signals at either 315 MHz or 433 MHz dependant on market
requirements.
The RF transmission from the sensor contains a unique identification code in its transmission data. This allows the TPMS to
identify the wheel on the vehicle. If the sensor is replaced on a wheel, the new sensor identification will be learnt through the
learn and location process.
The tire pressure sensor can also detect when the wheel is rotating. In order to preserve battery power, the sensor uses
different transmission rates when the wheel is stationary or moving.
NOTE: For important information regarding the removal and fitting of tire pressure sensors and associated valves, see the
Tire Changing section.
Instrument Cluster Indications
Item Description 1 Low tire pressure warning indicator 2 Message center Tire Pressure Sensor
The warning indications to the driver are common on all vehicles fitted with TPMS. The driver is alerted to system warnings by
a low tire pressure warning indicator in the instrument cluster and an applicable text message in the message centre.
The TPMS module passes system status information to the instrument cluster on the medium speed CAN bus. The instrument
cluster converts this data into illumination of the warning indicator and the display of an appropriate message.
When the ignition is switched on, the warning indicator is illuminated for 3 seconds for a bulb check.
NOTE: If the vehicle is not fitted with the TPMS, the warning indicator will not illuminate.
The instrument cluster checks, within the 3 second bulb check period, for a CAN bus message from the TPMS. During this time
the TPMS performs internal tests and CAN bus initialization. The warning indicator will be extinguished if the TPMS module
does not issue a fault message or tire pressure warning message.
If a TPMS fault warning message is detected by the instrument cluster at ignition on, the warning indicator will flash for 72
seconds after the 3 second bulb check period and then remain permanently illuminated.
If a tire pressure warning message is detected by the instrument cluster at ignition on, the warning indicator will extinguish
briefly after the 3 second bulb check period, before re-illuminating to indicate a tire pressure warning.
The following table shows the warning indicator functionality for given events:
Event Instrument Cluster Indications Low pressure warning limit reached in one wheel
Warning indicator illuminated. 'CHECK TYRE PRESSURE' message displayed
and applicable tire highlighted on display. Low pressure warning limit reached in one or
more wheels in low speed mode (only if programmed or learning) Warning indicator illuminated. 'CHECK ALL TYRE PRESSURES' message
displayed. TPMS fault
Warning indicator flashes for 72 seconds and is then permanently
illuminated. The flash sequence repeats after ignition on cycle. 'TYRE
PRESSURE SYSTEM FAULT' message displayed. No transmission from a specific tire pressure
sensor or Specific tire pressure sensor fault Warning indicator flashes for 72 seconds and is then permanently
illuminated. The flash sequence repeats after ignition on cycle. 'TYRE NOT
MONITORED' message displayed. No transmission from more than one tire pressure
sensor or more than one tire pressure sensor
fault Warning indicator flashes for 72 seconds and is then permanently
illuminated. The flash sequence repeats after ignition on cycle. 'TYRE
PRESSURE SYSTEM FAULT' message displayed. CAN (controller area network) signals missing
Warning indicator flashes for 72 seconds and is then permanently
illuminated. The flash sequence repeats after ignition on cycle. 'TYRE
PRESSURE SYSTEM FAULT' message displayed. Vehicle enters high speed mode (only available in
certain markets) Warning indicator illuminated. 'TYRE PRESSURE LOW FOR SPEED' message displayed.
7 Rear accelerometer 8 Instrument cluster 9 JaguarDrive selector module 10 ABS (anti-lock brake system) module 11 TCM (transmission control module) 12 ECM (engine control module) 13 RH (right-hand) rear damper 14 RH front damper 15 LH (left-hand) front damper 16 LH rear damper 17 LH rear suspension height sensor 18 RH rear suspension height sensor 19 LH front suspension height sensor 20 RH front accelerometer 21 RH front suspension height sensor 22 Adaptive damping module 23 LH front accelerometer
PRINCIPLES OF OPERATION System Operation
The adaptive damping module uses a combination of information from other system modules and data from the accelerometers
and suspension height sensors to measure the vehicle and suspension states and driver inputs. Using this information, the
adaptive damping module applies algorithms to control the dampers for the current driving conditions.
The adaptive damping module receives signals on the high speed CAN bus from the following system components: Brake Pressure - ABS module. Brake Pressure Quality Factor - ABS module. Car Configuration Parameters - AJB. Center Differential Range Actual - ECM. Engine Speed - ECM. Engine Speed Quality Factor - ECM. Engine Torque Flywheel Actual - ECM. Engine Torque Flywheel Actual Quality Factor - ECM. Gear Position Target - TCM. Lateral Acceleration - ABS module. Power Mode (Ignition Signal) - CJB. Power Mode Quality Factor - CJB. Roll Stability Control Mode - ABS module. Steering Wheel Angle - ABS module. Steering Wheel Angle Speed - ABS module. Steering Wheel Angle Status - ABS module. Terrain Mode Requested - JaguarDrive selector.
Torque Converter Slip - TCM. Vehicle Information Parameters HS - AJB Vehicle Speed - ABS module. Vehicle Speed Quality Factor - ABS module. Front Left Wheel Speed - ABS module. Front Left Wheel Speed Quality Factor - ABS module. Front Right Wheel Speed - ABS module. Front Right Wheel Speed Quality Factor - ABS module. Rear Left Wheel Speed - ABS module. Rear Left Wheel Speed Quality Factor - ABS module. Rear Right Wheel Speed Quality Factor - ABS module. Rear Right Wheel Speed - ABS module. The adaptive damping module also outputs information on the high speed CAN bus for use by other systems as follows: Fault Message - instrument cluster.
Terrain Mode Change Status - JaguarDrive selector.
Terrain Mode - JaguarDrive selector.
The adaptive damping module monitors the input signals and operates the damper solenoids. The input signals are used in
control modes and a force required for each damper for that mode is calculated. An arbitration mode monitors the force
requirements from each mode and apportions a force to a damper. The force is converted to the appropriate current and sent to
the damper.
The control modes are as follows:
1 ABS (anti-lock brake system) module 2 ECM (engine control module) 3 JaguarDrive Control selection buttons 4 Instrument cluster 5 TCM (transmission control module)
Published: 11-May-2011
Ride and Handling Optimization - Ride and Handling Optimization - Overview
Description and Operation
OVERVIEW
JaguarDrive Control is a selectable vehicle optimisation system, designed to fine-tune the driving characteristics of the vehicle
by accommodating different driving conditions or driving styles. The system allows the performance envelope of the vehicle to
be stretched and prevents the necessity for a single, compromised configuration for all conditions. JaguarDrive Control
increases the vehicle's abilities by changing the characteristics of engine mapping, transmission shifts and stability and
traction interventions. The software for the JaguarDrive control is incorporated in the JaguarDrive selector module.
NOTE: The JaguarDrive Control system is a co-ordinating system only. It CANNOT generate a fault in one of the
participating sub-systems. All participating subsystems should be FULLY diagnosed before assuming a fault with JaguarDrive
Control. Replacing the JaguarDrive selector module should not be done until all other options have been exhausted.
www.JagDocs.com
Published: 11-May-2011
Ride and Handling Optimization - Ride and Handling Optimization - System
Operation and Component Description
Description and Operation
JAGUARDRIVE CONTROL OPERATION
Engine Management System System Operation
The Engine Management System (EMS) varies the accelerator pedal maps to change the amount of torque per percentage of
pedal travel. The EMS can also change the accelerator pedal response to control the allowed torque change relative to the
speed of pedal travel.
Each driving mode uses a combination of operating parameters for each sub-system. Changing between driving modes initiates
a different set of operating characteristics, which will be noticeable to the driver. The driver will notice differences in engine
response when, for example, the accelerator pedal is held in a constant position and the driving mode is changed from Winter
to Dynamic, the driver will notice the torque and engine speed increase. Similarly, if the mode is changed from Normal or
Dynamic to Winter the driver will notice a reduction in torque and engine speed.
NOTE: The change in torque and engine speed can take approximately 30 seconds and care must be taken not to confuse
the JaguarDrive Control system operation with an EMS fault.
Transmission Control
The TCM (transmission control module) changes the shift maps for the JaguarDrive Control mode selected. This changes the
shift points providing early or late upshifts and downshifts. For example, on slippery surfaces in Winter mode the transmission
will select 2nd gear for starting from a standstill on a flat surface to minimize wheel slip.
Anti-lock Braking System Control
The ABS (anti-lock brake system) module controls several vehicle functions and adjusts the operating parameters of these
functions to optimize the selected JaguarDrive Control mode. Traction control uses different slip/acceleration thresholds to
improve traction and vehicle composure. For example, the system sensitivity is increased on slippery surfaces to reduce wheel
spin.
If TracDSC is selected or DSC is switched off, then subsequently the JaguarDrive Control mode is changed, DSC is automatically
switched back on (or to TracDSC for Dynamic mode).
The stability control uses different threshold values for the selected mode, reducing the requirement for the driver to change
the DSC system mode for optimum performance in various driving scenarios.
Incorrect Mode Usage
Selection of an inappropriate mode is discouraged in the following ways:
The active mode icon is continually displayed in the instrument cluster message center
In any special mode, when the ignition has been in the off position continuously for more than 6 hours, the JaguarDrive
Control system defaults to the special modes off (DSC on).
Selection of an inappropriate mode for the conditions will not endanger the driver or immediately cause damage to the vehicle.
Continued use of an inappropriate mode may reduce the life of some components. The driver may notice a different vehicle
response, with the engine and transmission responses being different than in the special modes off.
Driver Information
The instrument cluster contains a message center, which displays vehicle information to the driver. The message center
contains the JaguarDrive Control mode icons, which display the currently selected mode. If no symbol is displayed, no special
mode is selected and the system is in special modes off.
Any required changes to the subsystems are also passed to the driver in the form of warning illumination in the instrument
cluster or appropriate messages in the message center, DSC off for example.
In Dynamic mode when the transmission is in manual mode, the gear information is displayed in amber when the appropriate
engine speed is reached for optimum sporty change point.
DIAGNOSTICS
JaguarDrive Control relies on the correct functionality of the sub-systems. If one of the sub-systems develops a fault, the
JaguarDrive Control system will not function, even though the fault is not in the JaguarDrive Control system.
The JaguarDrive Selector module and rotary control should only be investigated if there are no apparent faults in any of the
sub-systems. If a fault in a sub-system is subsequently corrected, the JaguarDrive Control system will function normally after
an ignition on and off cycle.