2010 JAGUAR XFR traction control

Published: 11-May-2011
Anti-Lock Control - Stability Assist - Anti-Lock Control - Stability Assist - Overview
Description and Operation

Overview

The ABS (anti-lock brake system) and DSC (dynamic stability control) system features a Bosch modulator, which is an
integrated four-channel HCU (hydraulic control unit) and ABS module. The unit is located in the rear of the engine compartment on the passenger side, and is installed in the brake hydraulic circuit between the brake master cylinder and the four brake
calipers.

The ABS module is connected to the high speed CAN (controller area network) bus, and actively interacts with other vehicle system control modules and associated sensors to receive and transmit current vehicle operating information.

When required, the ABS module will actively intervene and operate the HCU during braking or vehicle maneuvers to correct the vehicle attitude, stability, traction or speed. During incidents of vehicle correction, the ABS module may also request the ECM (engine control module) to control engine power in order to further stabilize and correct the vehicle.
To provide full system functionality, the ABS and DSC system comprise the following components: DSC switch.
Four wheel speed sensors.
Steering angle sensor.
Yaw rate and lateral acceleration sensor.
Stoplamp switch.
Instrument cluster indicator lamps.
Integrated ABS module and HCU. Brake booster vacuum sensor (3.0L vehicles only).

Two variants of ABS module are available, Bosch ESP®8.1 and Bosch ESP®plus8.1. The Bosch ESP®plus8.1 system is fitted to vehicles with ACC (adaptive cruise control) and incorporates a new feature to Jaguar known as 'electronic brake prefill'.

Electronic brake prefill, senses any rapid throttle lift off, activating a small brake hydraulic pressure build-up of approximately 3
to 5 bar (43.5 to 72.5 lbf/in²) in anticipation of the brakes being applied. This application produces a quicker brake pedal
response and consequently slightly shorter stopping distances. When the ECM detects rapid throttle lift off it signals the ABS module which controls the HCU to apply a low brake pressure to assist in a quicker brake application.

NOTE: All vehicles with ACC are supported by the Bosch ESP®plus8.1 system.

The ABS provides the following brake functions that are designed to assist the vehicle or aid the driver: ABS. DSC, including Trac DSC.
CBC (corner brake control).
EBD (electronic brake force distribution).
ETC (electronic traction control).
EBA (emergency brake assist).
EDC (engine drag-torque control).
Understeer control.
Electronic brake prefill (vehicles with ACC only).
Brake vacuum assist (3.0L vehicles only).

All the brake functions listed are automatically active when the ignition is in power mode and the engine is running. The DSC
system can be selected to off using the DSC switch.


WARNING: Although the vehicle is fitted with DSC, it remains the drivers responsibility to drive safely according to the
prevailing conditions.

7 Brake fluid level switch 8 LH rear wheel speed sensor 9 RH rear wheel speed sensor 10 RJB (rear junction box) 11 High mounted stop lamp 12 LH stop lamp 13 RH stop lamp 14 Diagnostic socket 15 TCM (transmission control module) 16 Electronic parking brake module 17 ECM (engine control module) 18 Instrument cluster 19 ABS (anti-lock brake system) module 20 JaguarDrive selector module 21 Adaptive damping control module 22 Adaptive speed control module 23 Yaw rate and lateral acceleration sensor 24 Roof opening panel motor/module 25 Brake booster vacuum sensor (3.0L vehicles only) 26 Steering angle sensor


Anti-Lock Brake System System Operation

ABS controls the speed of all road wheels to ensure optimum wheel slip when braking at the adhesion limit. The wheels are prevented from locking to retain effective steering control of the vehicle.

The brake pressures are modulated separately for each wheel. Rear brake pressures are controlled to maintain rear stability on
split friction surfaces.

Dynamic Stability Control

DSC (dynamic stability control) uses brakes and powertrain torque control to assist in maintaining the yaw stability of the
vehicle. While the ignition is energized the DSC function is permanently enabled, unless selected off using the DSC switch.

DSC enhances driving safety in abrupt maneuvers and in under-steer or over-steer situations that may occur in a bend. The
ABS module monitors the yaw rate and lateral acceleration of the vehicle, steering input and individual wheel speeds, then selectively applies individual brakes and signals for powertrain torque adjustments to reduce under-steer or over-steer
conditions.
In general:

In an under-steer situation the inner wheels are braked to counteract the yaw movement towards the outer edge of the
bend.
In an over-steer situation the outer wheels are braked to prevent the rear end of the vehicle from pushing towards the
outer edge of the bend.

The ABS module monitors the tracking stability of the vehicle using inputs from the wheel speed sensors, the steering angle sensor, and the yaw rate and lateral acceleration sensor. The tracking stability is compared with stored target data. Whenever
the tracking stability deviates from the target data, the ABS module intervenes by applying the appropriate control strategy. The following interactions occur in an intervention situation:

High speed CAN signal to the ECM, to reduce engine torque. Application of braking to the appropriate corner of the vehicle.
Trac DSC

TracDSC is an alternative setting of DSC with reduced system interventions. With TracDSC engaged, traction may be somewhat
increased, although stability may be reduced compared to normal DSC. TracDSC is intended for use only on dry tarmac, by
suitably experienced drivers and should not be selected for other surfaces or by drivers with insufficient skill and training to
operate the vehicle safely with the TracDSC function engaged.

The less restrictive TracDSC setting may be preferred, for example, by expert drivers engaged in high performance driving on
dry Tarmac surfaces such as tracks and circuits.
Switching between DSC and Trac DSC:

Press and hold the DSC switch for less than 10 seconds.
The message center will temporarily display either Trac DSC or DSC ON.
The warning indicator in the instrument panel will illuminate while Trac DSC is selected.
The warning indicator will flash when DSC or Trac DSC is active.


NOTE: If cruise control is engaged, it will automatically disengage if DSC activates.

Refer to: Speed Control (310-03 Speed Control - 2.7L V6 - TdV6, Description and Operation).

Corner Brake Control

CBC (corner brake control) influences the brake pressures, below and within DSC and ABS thresholds, to counteract the yawing moment produced when braking in a corner. CBC produces a correction torque by limiting the brake pressure on one side of the
vehicle.

Electronic Brake Force Distribution

EBD (electronic brake force distribution) limits the brake pressure applied to the rear wheels. When the brakes are applied, the
weight of the vehicle transfers forwards, reducing the ability of the rear wheels to transfer braking effort to the road surface.
This may cause the rear wheels to slip and make the vehicle unstable.

EBD uses the ABS braking hardware to automatically optimize the pressure to the rear brakes, below the point where ABS is normally invoked.


NOTE: Only the rear brakes are controlled by the EBD function.
Electronic Traction Control

ETC (electronic traction control) attempts to optimize forward traction by reducing engine torque, or by applying the brake of a
spinning wheel until traction is regained.

ETC is activated if an individual wheel speed is above that of the vehicle reference speed (positive slip) and the brake pedal is
not pressed. The brake is applied to the spinning wheel, allowing the excess torque to be transmitted to the non-spinning
wheel through the drive line. If necessary, the ABS module also sends a high speed CAN bus message to the ECM to request a reduction in engine torque.

When the DSC function is selected off using the DSC switch, the braking and engine torque reduction features are both
disabled, except when the JaguarDrive control is in winter mode. When the JaguarDrive control is in winter mode, selecting the
DSC function off retains the braking and engine torque reduction features, but reduces intervention levels compared to DSC
and Trac DSC modes.

Emergency Brake Assist

EBA (emergency brake assist) assists the driver in emergency braking situations by automatically increasing the applied
braking effort. The ABS module invokes EBA when: The brake pedal is rapidly pressed.
The brake pedal is pressed hard enough to bring the front brakes into ABS operation.
When the brake pedal is rapidly pressed, the ABS module increases the hydraulic pressure to all of the brakes until the threshold for ABS operation is reached. This action applies the maximum braking effort for the available traction. The ABS module monitors for the sudden application of the brakes, using inputs from the brake pedal switch and from the pressure
sensor within the HCU (hydraulic control unit). With the brake pedal pressed, if the rate of increase of hydraulic pressure
exceeds the predetermined limit, the ABS module invokes emergency braking.
When the brake pedal is pressed hard enough to bring the front brakes into ABS operation, the ABS module increases the hydraulic pressure to the rear brakes up to the ABS threshold.
EBA operation continues until the driver releases the brake pedal, sufficiently for the hydraulic pressure in the HCU to drop below a threshold value stored in the ABS module.
Engine Drag-Torque Control
EDC (engine drag-torque control) prevents wheel slip caused by any of the following: A
sudden decrease in engine torque when the accelerator is suddenly released.
A downshift using the Jaguar sequential shift function on automatic transmission vehicles.

When the ABS module detects the onset of wheel slip without the brakes being applied, the ABS module signals the ECM via the high speed CAN bus to request a momentary increase in engine torque.
Understeer Control

Understeer Logic Control is a proactive system which monitors the vehicle for understeer by comparing signals from the yaw
rate and lateral acceleration sensor with signals from the steering angle sensor and wheel speed sensors. www.JagDocs.com

14 Radiator 15 Auxiliary radiator 16 Connection with supercharger cooling system
System Operation
When the engine is running, the coolant is circulated around the engine cooling system by the coolant pump. From the coolant
pump, coolant flows through the cylinder heads and the engine oil cooler into the cylinder block and the heater manifold.

In the cylinder block, the coolant flows forwards to the outlet tube. When the coolant is cold, the thermostat is closed and the
coolant flows direct from the outlet tube back to the coolant pump. Once the coolant reaches operating temperature the
thermostat begins to open, to control system temperature, and coolant flows from the outlet tube to the coolant pump via the
radiator and, on SC (supercharger) vehicles, the auxiliary radiator. When the thermostat is open, the coolant flow through the
radiator(s) also generates a coolant flow through the transmission fluid cooler.

From the heater manifold the coolant flows through the electronic throttle and the heater core, in parallel circuits that are
unaffected by the position of the thermostat. From the electronic throttle, the coolant merges with bleed coolant from the
coolant pump and the outlet tube and flows to the expansion tank. From the heater core, the coolant flows back to the inlet of
the coolant pump.

Expansion and contraction of the coolant is accommodated by an air space in the expansion tank and the compliance of the
flexible hoses.

If the coolant level in the expansion tank decreases below a predetermined value, the level sensor connects a ground to the
instrument cluster, which activates the appropriate warning. For additional information, refer to 413-01 Instrument Cluster.

The cooling fan is operated by a fan control module integrated into the cooling fan motor. The fan control module regulates the
voltage, and thus speed, of the cooling fan motor in response to a PWM (pulse width modulation) signal from the ECM (engine
control module).

The cooling fan receives a battery feed and an ignition feed from the EJB (engine junction box). The ignition feed is supplied
from the main relay in the EJB, which is controlled by the ECM.
The ECM calculates the required fan speed from the engine temperature, A/C (air conditioning) system pressure and transmission fluid temperature. Under hot operating conditions, the fan may continue to operate for 4 minutes after the engine
has been switched off.



COOLANT PUMP Component Description



Item Description 1 Inlet connection 2 Pump body 3 Outlet flange to RH cylinder head 4 Outlet to engine oil cooler 5 Outlet flange to LH cylinder head

Symptom Possible Causes Action Purge valve
Difficult hot start
Injector leak
Electronic engine control
Purge valve
Fuel pump
Ignition system
EGR valve stuck open Check for injector leak, install new injector as required.
Check for electronic engine controls, evaporative emissions,
fuel system, ignition system and engine emission system
related DTCs and refer to the relevant DTC Index Difficult to start after hot
soak (vehicle standing,
engine off, after engine has
reached operating
temperature)
Injector leak
Electronic engine control
Purge valve
Fuel pump
Ignition system
EGR valve stuck open Check for injector leak, install new injector as required.
Check for electronic engine controls, evaporative emissions,
fuel system, ignition system and engine emission system
related DTCs and refer to the relevant DTC Index Engine stalls soon after start
Breather system
disconnected/restricted
ECM relay
Electronic engine control
Ignition system
Air intake system restricted
Air leakage
Fuel lines Ensure the engine breather system is free from restriction
and is correctly installed. Check for electronic engine
control, ignition system and fuel system related DTCs and
refer to the relevant DTC Index. Check for blockage in air
filter element and air intake system. Check for air leakage
in air intake system Engine hesitates/poor
acceleration
Fuel pressure, fuel pump,
fuel lines
Injector leak
Air leakage
Electronic engine control
Throttle motor
Restricted accelerator pedal
travel (carpet, etc)
Ignition system
EGR valve stuck open
Transmission malfunction Check for fuel system related DTCs and refer to the
relevant DTC Index. Check for injector leak, install new
injector as required. Check for air leakage in air intake
system. Ensure accelerator pedal is free from restriction.
Check for electronic engine controls, ignition, engine
emission system and transmission related DTCs and refer
to the relevant DTC Index Engine backfires
Fuel pump/lines
Air leakage
Electronic engine controls
Ignition system
Sticking variable camshaft
timing (VCT) hub Check for fuel system failures. Check for air leakage in
intake air system. Check for electronic engine controls,
ignition system and VCT system related DTCs and refer to
the relevant DTC Index Engine surges
Fuel pump/lines
Electronic engine controls
Throttle motor
Ignition system Check for fuel system failures. Check for electronic engine
controls, throttle system and ignition system related DTCs
and refer to the relevant DTC Index Engine detonates/knocks
Fuel pump/lines
Air leakage
Electronic engine controls
Sticking VCT hub Check for fuel system failures. Check for air leakage in
intake air system. Check for electronic engine controls and
VCT system related DTCs and refer to the relevant DTC
Index No throttle response
Electronic engine controls
Throttle motor Check for electronic engine controls and throttle system
related DTCs and refer to the relevant DTC Index Poor throttle response
Breather system
disconnected/restricted
Electronic engine control
Transmission malfunction
Traction control event Air
leakage Ensure the engine breather system is free from restriction
and is correctly installed. Check for electronic engine
controls, transmission and traction control related DTCs and
refer to the related DTC Index. Check for air leakage in
intake air system DTC Index

For a list of Diagnostic Trouble Codes (DTCs) that could be logged in the Engine Control Module (ECM), please refer to Section
303-14.
REFER to: Electronic Engine Controls (303-14C Electronic Engine Controls - V8 5.0L Petrol, Diagnosis and Testing) / Electronic Engine Controls (303-14D Electronic Engine Controls - V8 S/C 5.0L Petrol, Diagnosis and Testing).

Symptom Possible Causes Action Difficult hot start
Injector leak
Electronic engine control
Purge valve
Fuel pump
Ignition system
EGR valve stuck open Check for injector leak, install new injector as required.
Check for electronic engine controls, evaporative emissions,
fuel system, ignition system and engine emission system
related DTCs and refer to the relevant DTC Index Difficult to start after hot
soak (vehicle standing,
engine off, after engine has
reached operating
temperature)
Injector leak
Electronic engine control
Purge valve
Fuel pump
Ignition system
EGR valve stuck open Check for injector leak, install new injector as required.
Check for electronic engine controls, evaporative emissions,
fuel system, ignition system and engine emission system
related DTCs and refer to the relevant DTC Index Engine stalls soon after start
Breather system
disconnected/restricted
ECM relay
Electronic engine control
Ignition system
Air intake system restricted
Air leakage
Fuel lines Ensure the engine breather system is free from restriction
and is correctly installed. Check for electronic engine
control, ignition system and fuel system related DTCs and
refer to the relevant DTC Index. Check for blockage in air
filter element and air intake system. Check for air leakage
in air intake system Engine hesitates/poor
acceleration
Fuel pressure, fuel pump,
fuel lines
Injector leak
Air leakage
Electronic engine control
Throttle motor
Restricted accelerator pedal
travel (carpet, etc)
Ignition system
EGR valve stuck open
Transmission malfunction Check for fuel system related DTCs and refer to the
relevant DTC Index. Check for injector leak, install new
injector as required. Check for air leakage in air intake
system. Ensure accelerator pedal is free from restriction.
Check for electronic engine controls, ignition, engine
emission system and transmission related DTCs and refer
to the relevant DTC Index Engine backfires
Fuel pump/lines
Air leakage
Electronic engine controls
Ignition system
Sticking variable camshaft
timing (VCT) hub Check for fuel system failures. Check for air leakage in
intake air system. Check for electronic engine controls,
ignition system and VCT system related DTCs and refer to
the relevant DTC Index Engine surges
Fuel pump/lines
Electronic engine controls
Throttle motor
Ignition system Check for fuel system failures. Check for electronic engine
controls, throttle system and ignition system related DTCs
and refer to the relevant DTC Index Engine detonates/knocks
Fuel pump/lines
Air leakage
Electronic engine controls
Sticking VCT hub Check for fuel system failures. Check for air leakage in
intake air system. Check for electronic engine controls and
VCT system related DTCs and refer to the relevant DTC
Index No throttle response
Electronic engine controls
Throttle motor Check for electronic engine controls and throttle system
related DTCs and refer to the relevant DTC Index Poor throttle response
Breather system
disconnected/restricted
Electronic engine control
Transmission malfunction
Traction control event Air
leakage Ensure the engine breather system is free from restriction
and is correctly installed. Check for electronic engine
controls, transmission and traction control related DTCs and
refer to the related DTC Index. Check for air leakage in
intake air system DTC Index

For a list of Diagnostic Trouble Codes (DTCs) that could be logged in the Engine Control Module (ECM), please refer to Section
303-14. REFER to:

Electronic Engine Controls (303-14C Electronic Engine Controls - V8 5.0L Petrol, Diagnosis and Testing), Electronic Engine Controls (303-14D Electronic Engine Controls - V8 S/C 5.0L Petrol, Diagnosis and Testing).

Published: 11-May-2011
Engine Emission Control - V8 5.0L Petrol/V8 S/C 5.0L Petrol - Engine Emission
Control
Diagnosis and Testing

Principles of Operation

For a detailed description of the engine emission control system and operation, refer to the relevant Description and Operation
section of the workshop manual. REFER to: (303-08C Engine Emission Control - V8 5.0L Petrol/V8 S/C 5.0L Petrol)

Engine Emission Control (Description and Operation), Engine Emission Control (Description and Operation), Engine Emission Control (Description and Operation).
Inspection and Verification


CAUTION: Diagnosis by substitution from a donor vehicle is NOT acceptable. Substitution of control modules does not
guarantee confirmation of a fault and may also cause additional faults in the vehicle being checked and/or the donor vehicle.


NOTE: Check and rectify basic faults before beginning diagnostic routines involving pinpoint tests.
1. Verify the customer concern.

2. Visually inspect for obvious signs of mechanical or electrical damage.

Visual Inspection
Mechanical Electrical
Exhaust gas recirculation system
Breather hoses
Positive crankcase ventilation valve
Fuel level
Fuel contamination/grade/quality
Throttle body
Fuses
Loose or corroded electrical connectors
Exhaust Gas Recirculation (EGR) valve
Engine Control Module (ECM)
3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to
the next step.

4. If the cause is not visually evident, verify the symptom and refer to the Symptom Chart, alternatively check for
Diagnostic Trouble Codes (DTCs) and refer to the DTC Index.

Symptom Chart

Symptom Possible Causes Action Difficult to
start cold
Battery
Crankshaft Position (CKP)
sensor
Exhaust Gas Recirculation
(EGR) valve stuck open
Fuel system
Evaporative emissions purge
valve For battery information, CKP sensor, fuel system and purge valve tests,
refer to relevant workshop manual section. Check the EGR valve. Engine stalls
soon after
start
Breather system
disconnected/restricted
Engine Control Module (ECM)
relay
MAF sensor
Ignition system
Air filter restricted
Air leakage
Fuel lines Check the engine breather hoses, PCV, etc. Check the Engine Control
Module (ECM) relay operation. For MAF sensor, ignition system tests, air
intake and fuel line information, refer to relevant workshop manual
section. Poor throttle
response
APP sensor malfunction
TP sensors
ECT sensor
MAF sensor
Transmission malfunction
Traction control event Air
leakage For APP, TP, ECT, MAF sensor tests, intake system checks and
transmission information, refer to relevant workshop manual section.
Check the breather system hoses, PCV, etc.

Symptom Possible Cause Action No throttle response
Electronic engine controls
Read DTCs and refer to DTC Index in this
section for electronic engine control tests Speed control inhibited or disabled
Default mode enabled
Speed control, brake switch
Electronic engine controls
CAN fault
Check message center for default message,
read DTCs and refer to DTC Index
Refer to the relevant section of the
workshop manual for speed control, and
brake switch tests.
Read DTCs and refer to DTC Index in this
section for electronic engine control tests
Refer to the relevant section of the
workshop manual and the electrical wiring
diagrams to perform CAN network tests. Poor throttle response
Breather system
disconnected/restricted
Electronic engine controls
Transmission malfunction
Traction control event
Air leakage
Ensure engine breather system is free from
restriction and is correctly installed
Read DTCs and refer to DTC Index in this
section for electronic engine control tests
Refer to the workshop manual or
transmission troubleshooting guide for
transmission system tests.
Check for leakage in air intake system Engine defaults, warning light and
messages. Refer to the owner
handbook
Electronic engine controls
Read DTCs and refer to DTC Index in this
section for electronic engine control tests DTC Index


WARNING: Fuel injector voltage will reach 65Volts during operation and have a high current requirement.


CAUTION: When probing connectors to take measurements in the course of the pinpoint tests, use the adaptor kit, part
number 3548-1358-00.
NOTES:


If the module/component is suspect and the vehicle remains under the Manufacturers warranty, refer to the Warranty
Policy and Procedure manual (section B1.2), or determine if any prior approval programme is in operation, prior to the
installation of a new module/component.


Generic scan tools may not read the codes listed, or may read only five digit codes. Match the five digits from the scan
tool to the first five digits of the seven digit code listed to identify the fault (the last two digits give additional information
read by the manufacturer-approved diagnostic system).


When performing electrical voltage or resistance tests, always use a digital multimeter (DMM) accurate to three decimal
places, and with an up-to-date calibration certificate. When testing resistance, always take the resistance of the DMM leads
into account.


Check and rectify basic faults before beginning diagnostic routines involving pinpoint tests.


If DTCs are recorded and, after performing the pinpoint tests, a fault is not present, an intermittent concern may be the
cause. Always check for loose connections and corroded terminals.

DTC Description Possible Causes Action B10A2-31 Crash Input - No signal
Loss of communication between
Restraints Control Module (RCM)
and Engine Control Module
(ECM) Refer to the electrical circuit diagrams and
check Restraints Control Module (RCM) Pulse
Width Modulated (PWM) SRS signal line circuit,
hard wired connection between Engine Control
Module (ECM) and Restraints Control Module
(RCM) for short to ground, short to power, open
circuit. Repair circuit as required, clear DTC and
retest system to confirm repair.