Land Rover Anti Lock Control Traction Control Rover Manual

							TERRAIN RESPONSE ROTARY CONTROL AND MODULE
Terrain Response rotary control1
Transfer box high/low range switch2
Air suspension switch3
Terrain Response control module4
Special programs off5
Grass/gravel/snow program6
Mud/ruts program7
Sand program8
Rock/crawl program9
HDC switch10
(G421055) Technical Training82
Lesson 2 – ChassisRide and Handling Optimization 
						

							The Terrain Response rotary control is located in the
center console and allows the selection of five operating
programs. Each program is denoted by a symbol which
represents the terrain encountered. The rotary control
can be rotated to select the required program. The
control will only select the last program in its direction
of rotation. Further rotation of the control once the last
program in either direction has been selected, will have
no effect, e.g. once rock crawl has been selected, further
rotation in a clockwise direction will have no effect.
The Terrain Response control module is located below
the rotary control. The module is connected via a harness
connector which also contains the wiring for the HDC
switch, the transfer box high/low range switch, the air
suspension switch and the switch illumination circuits.
The control module and switch uses four of these wires
for a 12V battery supply when the ignition switch is in
ignition position II, a ground and high speed CAN
positive and negative.
TERRAIN RESPONSE OPERATION
The following vehicle subsystem control modules are
used for the Terrain Response system:
•Engine management (engine control module)
•Transmission control (transmission control module
- automatic transmission only)
•Transfer box control (transfer box control module)
•Rear differential control (rear differential control
module - if fitted)
•Air suspension control (air suspension control
module)
•Brake system (ABS/DSC/ETC/HDC functions) (ABS
module)
Each subsystem operates in different ways in relation
to the selected Terrain Response program to achieve
the optimum traction, stability and ease of control for
the terrain encountered. The system has a safety factor
built in which ensures that any program can be safely
used on any surface, even when an inappropriate
program selection has been made.
Engine Management System (EMS)
The EMS varies the throttle pedal response to control
the engine torque output. The EMS can change the
throttle maps to change the amount of torque per
percentage of pedal travel. The EMS can also change
the throttle response to control the allowed torque
change relative to the percentage pedal travel.
Each terrain program uses a combination of operating
parameters for each subsystem. Changing between
terrain programs initiates a different set of operating
characteristics which will be noticeable to the driver.
The driver will notice differences in engine and throttle
response when, for example, the throttle pedal is held
in a constant position and the terrain program is changed
from grass/gravel/snow to sand, the driver will notice
the torque and engine speed increase. If the terrain
program is changed from sand to grass/gravel/snow 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 Terrain Response system operation with
an EMS fault.
Transmission Control
The transmission control module changes the shift maps
for the Terrain Response program selected. This changes
the shift points providing early or late upshifts and
downshifts.
On slippery surfaces the transmission will select 2nd
gear in high range or 3rd gear in low range for starting
from a standstill to minimise wheel slip. In muddy
conditions the transmission will provide maximum
Ride and Handling OptimizationLesson 2 – Chassis
83Technical Training (G421055) 
						

							torque output from the transmission. In sand the
transmission will provide an output which passes
maximum engine power from the transmission.
In rock crawl special program (low range) the
transmission will select 1st gear for driving off.
Sport mode is only available when the general program
is selected and the transfer box is in high range. Sport
mode is disabled in low range and all Terrain Response
special programs. CommandShift™ is available in any
program and also in high or low range.
If the transmission is in Sport mode and a special
program is subsequently selected, the transmission will
automatically change to manual CommandShift™
mode. If a special program is already selected and the
transmission selector lever is moved from drive D to
the Sport mode position, the transmission will
automatically change to CommandShift™ mode.
Transfer Box and Rear Differential Control
The transfer box electronically controlled differential
and the rear electronically controlled differential (if
fitted) are treated as one system. The electronic rear
differential is an optional fitment on vehicles fitted with
the Terrain Response system. The differential control
has two operating strategies; pre-emptive and reactive.
The pre-emptive strategy anticipates and predicts the
locking torque value required for each differential to
minimise slip and maximise stability. Each Terrain
Response program has a different threshold and input
criteria for the pre-emptive strategy. The pre-emptive
strategy improves vehicle traction and composure by
avoiding wheel spin. This is achieved by anticipating
the amount of differential lock required for the program
selected. For example, a high locking torque would be
applied for rock crawl or slippery surfaces.
The reactive strategy varies the amount of locking torque
in response to the actual slip level and the dynamic
behaviour of the vehicle. Each Terrain Response
program has a different threshold and input for the
reactive strategy. The reactive strategy improves vehicle
traction and composure by eliminating any wheel spin
which has occurred after the pre-emptive strategy was
applied. The locking response applied is applicable to
the terrain program selected, for example, very sensitive
on slippery surfaces to provide maximum traction and
minimise surface damage.
The locking torque calculations use various signals from
other subsystems, for example, engine torque, throttle
position, selected gear, steering angle, vehicle speed,
lateral acceleration, yaw behaviour.
The Dynamic Stability Control function of the ABS
system can override the Terrain Response differential
control and reduce any applied locking torque during
DSC action.
Air Suspension Control
The air suspension control module contains a strategy
which provides automatic switching between normal
and off-road heights. Changes in vehicle height settings
will be relayed to the driver via the instrument cluster
message center and LED illuminated icons on the
switch. The automatic selection and deselection of the
vehicle height provides automatic increase and decrease
in ground clearance and aims to provide maximum
benefit to the selected terrain program.
On a vehicle fitted with a correctly installed, Land Rover
approved trailer socket, if an electrical load is sensed
on the trailer socket, height changes are prohibited and
the message center displays a message advising that a
trailer is connected and off-road height is not
automatically selected. The driver can raise the
suspension manually using the air suspension switch.
NOTE: The prohibiting of the automatic ride height
selection is only operational if a Land Rover approved
trailer socket is fitted and an electrical load is sensed
on the socket.
(G421055) Technical Training84
Lesson 2 – ChassisRide and Handling Optimization 
						

							ABS Control
The ABS module controls several vehicle functions and
adjusts the operating parameters of these functions to
optimise the selected Terrain Response program.
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 DSC is switched off (with the DSC switch on the
instrument panel) when using a Terrain Response special
program, if the special program is subsequently changed
for a different program DSC is automatically switched
back on.
The stability control uses different threshold values for
the selected program to automatically reduce DSC
intervention, removing the requirement for the driver
to disable the DSC system in order to reduce engine
intervention which is sometimes induced in extreme
off-road conditions. In extreme sand conditions, there
may be an additional benefit of disabling the DSC
function using the DSC switch on the instrument panel
in addition to selecting the sand program.
HDC is automatically switched on or off and target
speeds are adjusted in response to the Terrain Response
program selected. The responsiveness of the HDC
function is also increased where required.
Automatic operation of HDC aims to assist the driver
by switching the system on or off when it is of most
benefit. Target speeds for HDC operation are also
adjusted according the vehicle operating conditions.
Incorrect Program Usage
Selection of an inappropriate program is discouraged
in the following ways:
•The active program icon is continually displayed in
the instrument cluster message center
•The Terrain Response control module locks out
certain functions in some programs, e.g. ,
•cruise control is only available with the special
programs off or grass/gravel/snow program
•transmission Sport mode is deactivated in all
special programs.
•When the ignition has been in the off position,
continually for more than six hours, the Terrain
Response system defaults to the special programs
off. (The dealer can prevent the Terrain Response
system defaulting out of the grass/gravel/snow
program using T4 or the driver can enable or disable
the default out of the grass/gravel/snow program
using the Customer Personalisation feature).
•The rock crawl program is only available with the
transfer box in low range.
Selection of an inappropriate program for the terrain
conditions will not endanger the driver or cause damage
to the vehicle. Continued use of an inappropriate
program may reduce the life of some components. The
driver may notice reduced vehicle response, with the
engine and transmission being less responsive than in
the special programs off. Also, in some programs, HDC
will remain on, signified by illumination of the HDC
indicator in the instrument cluster. The driver may also
notice torque wind-up in the center and rear
differentials causing a braking effect when the vehicle
is manoeuvred in some special programs.
The use of the special programs in the Terrain Response
system is monitored by the Terrain Response control
module which records the mileage and time the vehicle
has operated in a specific program in high and low
range. This information can be retrieved using T4 and
used by the dealer technician to check customer
concerns, e.g. high fuel consumption which may be due
to continued use of a certain program.
Ride and Handling OptimizationLesson 2 – Chassis
85Technical Training (G421055) 
						

							Driver Information
The high specification instrument cluster fitted to all
vehicles with Terrain Response, contains a message
center which displays vehicle information to the driver.
The message center contains the Terrain Response
program icons which display the currently selected
program. If no symbol is displayed, no special program
is selected and the system is in special programs off.
Any required changes to the subsystems are also passed
to the driver in the form of indicator illumination in the
instrument cluster or appropriate messages in the
message center, HDC off or air suspension height
change for example.
In certain operating conditions, the Terrain Response
system also displays advice or warning messages to
ensure the driver is using the vehicle to its full potential,
e.g.,
•Steering angle is displayed in the message center to
avoid driving in deep ruts with steering lock applied
•gear information is displayed to recommend a gear
for slippery conditions
•if the system automatically provided off road ride
height, but the driver subsequently lowers the vehicle
to normal height, then the system may advise that
this will cause a risk of grounding.
The messages which can be displayed in the instrument
cluster message center are detailed in the Information
and Message Center section.
DIAGNOSTICS
The Terrain Response control module stores information
on detected Terrain Response faults and CAN errors
which can be interrogated using T4. The Terrain
Response sub-systems and the instrument cluster also
store fault information relating to CAN errors from the
Terrain Response control module.
The control module also stores the miles travelled and
time elapsed in high range for the individual programs
and in low range for use of all programs which can also
be retrieved using T4. This information aids diagnosis
of the Terrain Response system and also provides an
indication of Terrain Response system abuse by the
driver which can lead to premature component failure.
Terrain Response System Fault Diagnosis
Terrain Response relies on the correct functionality of
the five sub-systems. If one of the sub-systems develops
a fault, the Terrain Response system will not function,
even though the fault is not in the Terrain Response
system. The Terrain Response control 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 Terrain
Response system will function normally after an ignition
on and off cycle.
Terrain Response Sub-System Faults
If a fault occurs in a sub-system, the driver is alerted by
the illumination of a warning indicator and/or an
appropriate message for that sub-system in the
instrument cluster message center. There will be no
warning of a Terrain Response system fault.
When a sub-system fault is present and the driver
attempts to select a different Terrain Response program
using the rotary control or at the next ignition on cycle,
a message SYSTEM FAULT SPECIAL PROGRAMS
NOT AVAILABLE will appear in the message center.
This implies that the Terrain Response system has a
fault, but only because a sub-system fault is preventing
its operation. This message will be displayed for 5
seconds per ignition cycle, but is repeated if a further
selection is made by the driver using the Terrain
Response rotary control or at the next ignition on cycle.
(G421055) Technical Training86
Lesson 2 – ChassisRide and Handling Optimization 
						

							NOTE: The message SYSTEM FAULT SPECIAL
PROGRAMS NOT AVAILABLE can also be generated
by a fault in the Terrain Response rotary control or
control module. See following section for details of
rotary control or control module faults.
It is not possible for the Terrain Response control
module to cause any fault behaviour (warning indicator
illumination or message generation) in any of the five
sub-systems. Illumination of a sub-system warning
indicator and/or a sub-system related message will never
be associated with a Terrain Response control module
or Terrain Response system fault.
The sub-system control modules can detect a fault with
the CAN signal from the Terrain Response control
module. If a fault in the Terrain Response system is
detected, the sub-system control modules will operate
in the special programs off setting. The sub-system
control modules will record a fault code for a failure of
the Terrain Response CAN signal. These faults can be
retrieved using T4 and will provide useful information
to indicate investigation of the Terrain Response control
module or the CAN network.
Terrain Response Rotary Control or Control Module
Fault
If a fault occurs in the Terrain Response rotary control,
all rotary control icon amber LEDs will be turned off
(background illumination will remain on) and rotation
of the rotary control is ignored. The instrument cluster
message center will display a message SYSTEM
FAULT SPECIAL PROGRAMS NOT AVAILABLE
when the fault occurs, if the fault is present and the
driver attempts to select a special program (if the control
module is able to do this) or at the next ignition on cycle.
If a failure of a rotary control icon amber LED occurs,
the Terrain Response system will still function. Any
selected special program will default to special
programs off at every ignition on cycle, except if default
from grass/gravel/snow program has been disabled, in
which case the grass/gravel/snow program will remain
selected.
The Terrain Response rotary control and the control
module are an integral unit. If a fault occurs in either
component, the whole unit will require replacement.
CAN Faults
If a CAN fault exists and prevents Terrain Response
system operation, all of the Terrain Response rotary
control icon LEDs will be illuminated and rotation of
the rotary control is ignored.
If the instrument cluster does not receive a Terrain
Response system CAN message from the Terrain
Response Control module, the message SYSTEM
FAULT SPECIAL PROGRAMS NOT AVAILABLE
will be displayed when the fault occurs and will be
repeated at every ignition on cycle.
User Error
The following incorrect usage of the system may be
misinterpreted as a system fault:
•Engine not running - Program changes and driver
advisory messages are only available with the engine
running
•Rock crawl program selected but transfer box in high
range
•Special program change attempted with DSC or ABS
active (this includes ABS cycling which is
operational when HDC is being used on slippery or
loose surfaces).
•Special program change attempted with overheat
condition present on center or rear differential.
Ride and Handling OptimizationLesson 2 – Chassis
87Technical Training (G421055) 
						

							Workshop safety
This page highlights the general observations expected
whilst attending this training programme, and its
continuation upon returning to your place of work.
General
Whilst working on all vehicles, the following items
where available should always be used:
•Wing covers
•Seat covers
•Floor protection
Optional items:
•Steering wheel cover
•Park brake lever cover
•Door grab handle protection
Safety
All precautions must be taken and observed at all times,
to prevent injury or damage to the following:
•Yourself
•Customers property
•Workshop equipment
•Work place colleagues
Operating guidelines
Whilst using any piece of workshop equipment:
The manufacturers guidelines and warning labels must
be followed.
This will ensure correct use and application at all times.
Seek the necessary advice or training where equipment
usage is unclear.
Chemicals, Oils and Solvents
Follow all manufacturers warnings and labels, also take
into account local disposal regulations when working
with chemicals, oils or solvents.
Ensure that all risks are completely minimised.
Make sure that all protective items of clothing are worn
where required, e.g.
•Eye protection
•Gloves
•Overalls
•Footwear
System capping
Upon disconnecting components from a system, take
all precautions necessary to prevent system
contamination or environmental leakage.
Fit relevant plugs or caps, i.e. to pipes, unions and
component orifices, etc.
Updates
Keep abreast of all relevant changes that effect your
role within the dealership, by monitoring all factory
issued documentation.
Driving
Operating vehicle features, such as ICE, mobile phones
and CD player equipment etc, can cause a momentary
distraction whilst driving.
Follow all road traffic regulations as written in the
Highway Code, when operating vehicle systems or using
diagnostic equipment whilst on the move.
Mobile diagnostic equipment operation, may require
the use of an assistant.
Safety and Precautions
7 
						

							Notes 
						

							Dynamic Suspension - Component Location
NOTE: Right hand drive vehicle shown
Front RH air spring damper module1Front RH height sensor2
Vehicle Dynamic SuspensionLesson 2 – Chassis
51Technical Training (G421053) 
						

							Air suspension control module3
Air suspension control switch4
Rear RH height sensor5
Rear RH air spring damper module6
Air supply unit silencer7
Rear LH air spring damper module8
Air filter9
Rear valve block10
Rear LH height sensor11
Upper acoustic cover12
Lower acoustic cover13
Air supply unit14
Reservoir valve block15
Air reservoir16
Front LH height sensor17
Front LH air spring damper module18
Front valve block19
GENERAL
NOTE: This section covers the air suspension control
system.
Front suspension is detailed in a separate section.
Rear suspension is detailed in a separate section.
Terrain Response™ is detailed in a separate section.
The dynamic suspension system is a four corner air
suspension system which is fitted to higher specification
vehicles in place of the conventional damper and coil
spring suspension used on non-air suspension models.
The dynamic suspension system is electronically
controlled by an air suspension control module which
controls the air supply unit, reacts to inputs from four
height sensors and distributes air around the system via
valve blocks.
The main air suspension system components are:
•Air suspension control module
•Air supply unit
•Four height sensors
•Three valve block assemblies
•Reservoir
•Air harness
•Four suspension air spring damper modules.
The four corner air suspension system maintains the
vehicle height under all operating conditions by
controlling the mass of air in the air springs. The air
suspension control module uses signals from the four
height sensors to maintain the correct suspension height.
This is achieved by operating pneumatic control valves
to increase or decrease the mass of air in the air spring
damper modules.
The air suspension system has three driver selectable,
pre-determined ride heights. A driver interface indicates
the selected ride height and direction of movement.
Additional information is also relayed to the driver via
the instrument cluster message center (where fitted) and
by audible warnings also transmitted by the instrument
cluster.
Height changes can only be made when the engine is
running and the drivers and passenger doors are closed.
Access height can be selected with the engine not
running, within 40 seconds of moving the ignition
switch to the off position provided the drivers door has
not been opened in this time.
The air suspension can be controlled manually by the
driver using a switch on the center console to select the
required height change.
(G421053) Technical Training52
Lesson 2 – ChassisVehicle Dynamic Suspension