Land Rover Anti Lock Control Traction Control Rover Manual

							Schematic Pneumatic Circuit
Compressor1
Compressor temperature sensor2
Air dryer3
Reservoir4
Front LH air spring damper module5
Front valve block6
Cross link valve7
Front RH air spring damper module8
Front RH corner valve9
Front LH corner valve10
Reservoir control valve11
Pressure sensor12
Rear RH corner valve13
Rear RH air spring damper module14
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							Cross link valve15
Rear valve block16
Rear LH corner valve17
Rear LH air spring damper module18
Inlet air filter19
Pilot exhaust valve20
Exhaust21
Air silencer22
Pressure relief and exhaust valve23
Motor temperature sensor24
Electric motor25
OPERATING MODES
The driver can manually select, using the air suspension
switch, one of four ride states:
•ON-ROAD - this height is the normal operating
height of the vehicle
•OFF-ROAD - this height is higher than the on-road
height and provides improved ground clearance,
approach, departure and breakover angles
•ACCESS - this height is lower than the on-road
height and makes entering and exiting the vehicle
easier for the occupants
•CRAWL (Locked at access) - this height allows the
vehicle to be driven at the access height at low speeds
to provide increased roof clearance in low car parks
etc.
NOTE: Vehicle height changes are prevented if the air
suspension control module receives a Door Open signal
from the Central Junction Box (CJB).
An additional TRANSPORTATION mode is also
available but is only selectable using T4.
An additional function allows the vehicle to be raised
or lowered from outside of the vehicle when the vehicle
is stationary. This assists with the attachment of a trailer
and is achieved using the buttons on the remote handset
and the ignition switch in the off position. The remote
handset can be programmed to perform a number of
additional functions.
If the air suspension control module senses that the
vehicle has grounded and lost traction, the control
module can temporarily increase and/or redistribute the
volume of air supplied to the affected air spring(s) to
maximise the available traction. This is known as
extended mode and will be indicated to the driver by
the lamps on the air suspension switch flashing.
If the air suspension control module senses that the
vehicle is prevented from moving upwards or
downwards during a height change or levelling
correction, the control module will adopt a safe state
and further height changes will be suspended.
If a fault is detected by the air suspension control
module, the control module will reduce the system
functionality dependent on the type and severity of the
fault. The control module will also store a fault code
which can be retrieved using T4. If a severe fault occurs,
the control module will attempt to put the vehicle in a
safe condition. A fault is relayed to the driver by the
illumination of the air suspension warning indicator,
the instrument cluster message center and an audible
warning emitted from the instrument cluster.
If the detected fault is minor and does not affect vehicle
safety, the air suspension warning indicator in the
instrument cluster will illuminate in an amber colour
and the fault should be rectified at the earliest
opportunity. If a more severe fault is detected above 31
mph (50 km/h) vehicle speed, the warning indicator will
illuminate in a red colour and the vehicle should be
driven with care until the fault is rectified. An audible
warning is emitted by the instrument cluster sounder
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							when the warning indicator is illuminated. The indicator
will change to an amber color and the audible warning
will stop when the vehicle speed is reduced.
On-Road Mode
This is the normal ride height for the vehicle.
Off-Road Mode
Off-road mode will only be activated if the vehicle speed
is less than 25 mph (40 km/h). The vehicle will be raised
55 mm (2.2 in) higher than the on-road mode to provide
additional body clearance and improved approach,
departure and breakover angles. If the vehicle speed
exceeds 31 mph (50 km/h), the air suspension control
module will automatically lower the vehicle to the
on-road mode height. At 25 to 28 mph (40 to 45 km/h)
a message is displayed in the message center to warn
the driver to slow down or the vehicle will lower.
NOTE: The suspension can be automatically set to
off-road mode when some Terrain Response programs
and low range are selected.
Access Mode
Access mode lowers the vehicle body height by 50 mm
(2 in) and provides easier entry, exit and loading of the
vehicle. Access mode can be pre-selected when the
vehicle is moving. The vehicle will partly lower as the
vehicle speed decreases, lowering to the full access
mode height when the vehicle reaches 5 mph (8 km/h).
If the required road speed is not reached within a
predetermined time, the air suspension will return the
vehicle to the previously selected height.
Access mode can be selected at any vehicle speed. When
access mode is selected, the response of the air
suspension system will depend on the vehicle speed:
•If the vehicle speed is more than 12.5 mph (20 km/h),
the air suspension control module will wait for up
to one minute for the vehicle speed to be reduced.
The access mode lamp and the lowering lamp will
flash while the air suspension control module waits
for the vehicle speed to be reduced, the on-road mode
lamp will remain illuminated. If the vehicle speed is
not reduced sufficiently, the access mode request
will be cancelled after 1 minute.
•If the vehicle speed is less than 12.5 mph (20 km/h),
the air suspension control module will lower the
suspension to a part lowered height and will remain
at this height for up to one minute. The on-road mode
lamp will extinguish as the air suspension control
module lowers the suspension to the part lowered
height. The access mode lamp and the lowering lamp
will illuminate. When part lowered is reached, the
lower lower lamp will flash. If the vehicle speed is
not reduced to less than 5 mph (8 km/h) in the one
minute period, the access mode request will be
cancelled.
•If the vehicle speed is less than 5 mph (8 km/h), the
suspension will be lowered to access mode
immediately. The access mode lamp and the lowering
lamp will illuminate. When the access mode height
is reached, the lowering lamp will be extinguished.
Access height may be selected up to 40 seconds after
the ignition is turned off, provided that the drivers door
has not been opened within this time.
The suspension will automatically rise from access mode
when the vehicle speed exceeds 6.2 mph (10 km/h). If
access mode was selected directly from off-road mode
then the system will return to off-road mode when the
vehicle speed exceeds 6.2 mph (10 km/h). Otherwise
the system will lift the suspension to On-road height.
Selecting Access Mode Directly from Off-Road Mode
When the suspension is in off-road mode height,
pressing the air suspension switch once and then a
second time before the lowering lamp is extinguished,
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							the control module will lower the suspension to access
mode height. The control module will remember to
return the suspension to off-road height automatically
if the vehicle speed increases above 6.2 mph (10 km/h).
Crawl (Locked at Access) Mode
Crawl mode allows the vehicle to driven at access
height. The vehicle is locked in access height and can
be selected at a speed of less than 21.7 mph (35 km/h)
and can be driven at low speeds to improve clearance
in areas with restricted headroom, i.e. car parks. If the
vehicle exceeds 24.8 mph (40 km/h), crawl mode will
be cancelled and the vehicle will return to on-road
height.
Crawl mode allows the vehicle to be driven at low
speeds with the suspension locked at the access mode
height. This allows the vehicle to be driven in low car
parks etc. with increased roof clearance.
Crawl mode can be selected up to 21.7 mph (35 km/h)
with a long press of the switch in the down direction.
The access mode lamp and the crawl mode lamp will
be illuminated. When the control module is in crawl
mode, on-road mode height will be selected
automatically if the vehicle speed exceeds 25 mph (40
km/h). At 18.6 to 21.7 mph (30 to 35 km/h) a message
is displayed in the message center to warn the driver to
slow down or the vehicle will raise. Crawl mode can
also be manually cancelled by moving the switch in the
up direction for 1 second. The access mode lamp and
the crawl mode lamp will be extinguished.
Automatic Height Change Warnings
When the suspension is in off-road mode, access mode
or crawl mode height, the air suspension control module
will change the suspension height automatically when
the vehicle speed exceeds a predetermined threshold.
When the suspension is at off-road mode or crawl mode
height, the control module issues a warning to advise
the driver that the vehicle is approaching the speed
threshold. The instrument cluster sounder will emit a
chime, a message will be displayed in the message
center and the on-road mode lamp and either the raising
or lowering lamp will flash.
The off-road mode or crawl mode height speed warning
is removed when the vehicle speed is reduced.
SPECIAL MODES
Door Open Functionality
If one or more of the vehicle doors are opened during
a height change when the vehicle is stationary, the air
suspension control module will restrict further height
change. The door open signal is transmitted by the CJB
on the high speed CAN bus and received by the air
suspension control module. This keeps the vehicle level
to the set height when a door opens to allow for changes
in loading conditions.
A hardwired door status signal is also transmitted from
the CJB to the air suspension control module. This signal
provides door status information when the high speed
CAN bus is off, i.e.; during periodic re-levelling.
The lamp on the air suspension switch for the target
mode height will remain illuminated and the raising or
lowering lamp will flash.
If all of the doors are closed within 90 seconds, the
height change will resume. If the 90 second period is
exceeded and all of the doors are not closed, the height
change will be cancelled. The mode lamps showing the
previously selected height and the target height will be
illuminated. The mode height change can be reselected
by operating the switch, however, if the vehicle is driven
at speed of more than 5 mph (8 km/h) the control
module will continue to raise or lower the vehicle to the
target mode height.
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							Extended Mode
If the vehicle becomes grounded and the traction control
becomes operational, the air suspension control module
automatically increases the mass of air in the air springs
to raise the vehicle clear of the obstruction. Extended
mode is activated automatically and cannot be selected
manually.
When the air suspension control module has activated
the extended mode, the off-road mode lamp will flash
if the suspension is above off-road mode height. The
off-road mode and on-road mode lamps will flash if the
suspension is between off-road mode and on-road mode
heights. The on-road mode and access mode lamps will
flash if the suspension is between on-road mode and
access mode. A message will also be displayed in the
message center.
To exit the extended mode, press the air suspension
switch briefly in the up or down position or drive the
vehicle at a speed of more than 12.5 mph (20 km/h).
Suspension Prevented From Moving
If the air suspension control module is attempting to
change the suspension height and it detects that the
suspension is prevented from moving, the control
module will stop all suspension movement. This can be
caused by jacking the vehicle, attempting to lower the
vehicle onto an object or raising the vehicle against an
obstruction.
The air suspension switch lamps operate as described
for extended mode and the same message is displayed
in the message center. To start the air suspension system
operating, press the air suspension switch briefly in the
up or down position or drive the vehicle at a speed of
more than 12.5 mph (20 km/h).
Periodic Re-levelling
When the vehicle is parked, the air suspension control
module wakes up two hours after the ignition was last
switched off and then once every six hours. The vehicle
height is checked and if the vehicle is not level within
a pre-set tolerance, small downwards height adjustments
may be made automatically.
Transportation Mode
Transportation mode is a factory set mode which locks
the suspension to enable the vehicle to be safely lashed
to a transporter. Transportation mode can only be
selected or deselected using T4.
When the ignition switch is switched off, the vehicle
will be lowered onto the bump stops. This ensures that
the securing straps do not become loose should air leak
from the air springs.
When the engine is running, the air supply unit will
operate to raise the vehicle height, allowing the vehicle
to be loaded. When the ignition switch is subsequently
switched off, the vehicle will again lower onto the bump
stops. An audible warning will be emitted from the
instrument cluster sounder until the vehicle has reached
the higher transportation height.
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							AIR SUSPENSION CONTROL MODULE
Air suspension control module1
Connector C08672
Connector C23203
Connector C20304
Connector C23215
The air suspension control module is located behind the
instrument panel, on the drivers side A post. The
control module is attached to the A post with a single
screw and two plastic clips.
Calibration
A calibration routine is performed using T4 to access
the position of each corner of the vehicle and record the
settings in the ECU memory. Once set, the calibration
is not required to be performed unless the air suspension
control module is removed or replaced, a height sensor
is removed or replaced or a suspension arm to which
the sensor is connected is removed or replaced. If the
removed height sensor is subsequently refitted, the
calibration procedure will have to be performed to
ensure the integrity of the system.
If the air supply unit, the reservoir, a valve block, a
damper module or the air harness is removed or
replaced, the system will not require recalibration.
Inputs and Outputs
The air suspension control module uses four harness
connectors for all inputs and outputs.
The following tables show the details of the signals or
electrical supplies on each connector pin.
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							Connector C2030
Input/OutputDescriptionPin No.
OutputRear control valve - Cross link valve - positive (+)1
-Not used2
-Not used3
-Not used4
InputAir supply unit - Motor temperature sensor signal5
-Not used6
InputAir supply unit - Motor temperature sensor - Ground7
OutputSwitch pack display - Raising LED8
OutputSwitch pack display - Lowering LED9
OutputSwitch pack display - On-road mode LED10
InputRear control valve - Cross link valve - negative (-)11
-Not used12 to 16
OutputSwitch pack display - Crawl mode LED17
OutputSwitch pack display - Access mode LED18
-Not used19
InputSwitch pack - Raise switch signal20
Connector C2320
Input/OutputDescriptionPin No.
InputAir supply unit voltage signal input from Air supply unit
relay
1
OutputReservoir control valve - Pressure sensor - 5 Volt supply2
InputReservoir control valve - Pressure sensor - Signal3
InputReservoir control valve - Pressure sensor - Ground4
InputAir supply unit - Exhaust valve - Negative (-)5
OutputAir supply unit - Exhaust valve - Positive (+)6
-Not used7 and 8
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							Connector C2321
Input/OutputDescriptionPin No.
Input12V Permanent battery supply1
InputCompressor temperature sensor - Signal2
OutputFront LH height sensor - 5 Volt supply3
InputFront LH height sensor - Signal4
InputFront LH height sensor - Ground5
OutputAir supply unit relay coil - positive6
InputAir supply unit relay coil - ground7
OutputReservoir control valve coil - positive (+)8
InputFront control valve - RH corner valve - negative (-)9
OutputFront control valve - RH corner valve - positive (+)10
InputFront control valve - LH corner valve - negative (-)11
OutputFront control valve - LH corner valve - positive (+)12
-Not used13
OutputFront RH height sensor - 5V supply14
InputFront RH height sensor - signal15
InputFront RH height sensor - ground16
InputCompressor temperature sensor - ground17
-Not used18 to 20
InputReservoir control valve coil - negative (-)21
OutputFront control valve - cross link valve - positive (+)22
InputFront control valve - cross link valve - negative (-)23
InputGround24
Connector C0867
Input/OutputDescriptionPin No.
OutputRear control valve - LH corner valve positive (+)1
InputRear control valve - LH corner valve negative (-)2
InputDoor status signal from CJB3
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							Input/OutputDescriptionPin No.
InputSwitch pack - Lower switch signal4
OutputRear LH height sensor - 5 Volt supply5
InputRear LH height sensor - Signal6
InputRear LH height sensor - Ground7
OutputRear RH height sensor - 5 Volt supply8
InputRear RH height sensor - Signal9
InputRear RH height sensor - Ground10
OutputRear control valve - RH corner valve positive (+)11
InputRear control valve - RH corner valve negative (-)12
InputAir suspension control - CJB signal13
InputSwitch pack display - LED ground14
OutputSwitch pack display - LED high15
InputCAN IN positive (+)16
OutputCAN OUT positive (+)17
InputCAN OUT negative (-)18
OutputCAN IN negative (-)19
Input12 Volt ignition switch supply20
The air suspension control module uses inputs received
on the CAN bus from other vehicle systems. The system
uses longitudinal acceleration, lateral acceleration,
steering angle and wheel speed data to control the
suspension operation in differing driving conditions.
The system will react differently if one or more of these
data inputs is missing or incorrect, for example, if the
steering angle sensor is missing or incorrect, the air
suspension control module assumes a default value of
zero which may result in some unnecessary levelling
activity.
Air Supply Unit Relay
The air supply unit relay is located in the battery
junction box in the engine compartment. The relay is
connected directly to the battery via fusible link 10E
(60A). The relay coil is connected to and controlled by
the air suspension control module. The relay is used by
the air suspension control module to control the
operation of the compressor.
When air supply unit operation is required, the air
suspension control module supplies power and ground
for the relay coil which energises, closing the relay
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							contacts. This allows battery voltage via the fusible link
to pass through the relay and operate the air supply unit
electric motor and the compressor.
The battery voltage is also passed from the relay, via a
splice joint in the harness, to the air suspension control
module and is used as a signal that the air supply unit
is operating.
System Inhibits
A number of conditions exist where a change of ride
height is undesirable. To counter this, the air suspension
control module is programmed with a number of system
inhibits. If any of the conditions detailed below exist,
the air suspension control module will suspend height
changes and height corrections.
Compressor
The temperature sensors located within the compressor
protect the compressor from overheating. If the
compressor temperature rises above set limits, the air
suspension control module will inhibit the compressor
operation. These limits are shown in the following table:
Compressor Head Temperature Sensor
Filling ReservoirLifting
140°C (284°F)150°C (302°F)Stop
120°C (248°F)130°C (266°F)Start
Compressor Brush Temperature Sensor
Filling ReservoirLifting
130°C (266°F)140°C (284°F)Stop
110°C (230°F)120°C (248°F)Start
Cornering
If the air suspension control module registers a cornering
force greater than 0.2g it will inhibit all height changes
and corrections. The system will remain inhibited until
the cornering force falls to less than 0.15g. The air
suspension control module receives a message from the
lateral acceleration sensor (which is an integral part of
the ABS yaw rate sensor) on the high speed CAN bus
for the cornering force.
Rapid Acceleration
If the air suspension control module registers a rapid
acceleration greater than 0.2g it will inhibit all height
changes and corrections. The system will remain
inhibited until the rapid acceleration falls to less than
0.15g. Acceleration is calculated by the air suspension
control module from a vehicle speed signal received via
the high speed CAN bus.
Rapid Deceleration
If the air suspension control module registers a rapid
deceleration smaller than -0.2g it will inhibit all height
changes and corrections. The system will remain
inhibited until the rapid deceleration rises above -0.15g.
Deceleration is calculated by the air suspension control
module from a vehicle speed signal received via the
high speed CAN bus.
Vehicle Jack
The air suspension control module will inhibit all height
changes and corrections if it detects a corner lowering
too slowly for more than 1.2 seconds. This is interpreted
as the corner identified as moving too slowly being
supported on a jack. In this situation, the corner height
will not change when air is released from the air spring
because the jack acts as a mechanical prop. The system
will remain inhibited until any of the following
conditions exist:
•The air suspension switch is moved to the up or down
position
•Vehicle speed rises to more than 9.3 mph (15 km/h)
for more than 15 seconds.
Door Open
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