L322 Range Rover System Description and Operation
SUSPENSION
DESCRIPTION AND OPERATION
60-23
Compressor Timeout
Compressor operation will be halted after 180 seconds of continuous operation. If the compressor was attempting to
regulate vehicle height, it remains inhibited for 20 seconds. If the compressor was attempting to fill the air suspension
reservoir, it remains inhibited for 180 seconds. These time out functions act as a further safe guard against over
heating.
Cornering
If the air suspension ECU 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 for 0.5 seconds. The air suspension
ECU receives a message from the ABS sensor on the CAN Bus for the cornering force.
Rapid Acceleration
If the air suspension ECU 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 0.2g for 1 second.
Acceleration is calculated by the ECU from a vehicle speed signal received via the CAN bus.
Rapid Deceleration
If the air suspension ECU 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 – 0.2g for 1 second. Deceleration
is calculated by the ECU from a vehicle speed signal received via the CAN bus.
Axle Articulation
To avoid excess pressure differentials between different air springs, the air suspension ECU will inhibit all height
changes and corrections if axle articulation is greater than 350 mm. The system will remain inhibited until axle
articulation falls below 350 mm.
Vehicle Lift
The air suspension ECU will inhibit all height changes and corrections if it detects all four corner heights are greater
than 90 mm. This is interpreted as the vehicle being on a wheels free car lift with all wheels hanging freely. In this
situation, the corner heights will not change when air is released from the air springs. The system will remain inhibited
until any of the following conditions exist:
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All four corner heights fall below 90 mm
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The rotary switch is moved to the 'UP' or 'DOWN' position.
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Vehicle speed rises to greater than 25 mph (40 km/h) for longer than 3 seconds.
Vehicle Jack
The air suspension ECU will inhibit all height changes and corrections if it detects a corner lowering too slowly for
more than 3 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:
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The height of the wheel identified as lowering too slowly, returns to the height where jacking was detected.
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The rotary switch is moved to the 'UP' or 'DOWN' position.
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Vehicle speed rises to greater than 25 mph (40 km/h) for longer than 3 seconds.
Door Open
The air suspension ECU will stop all height change requests while any of the doors are open. Vehicle levelling is also
inhibited with a door open.
Trailer Mode
Using the electrical trailer connection will cause the air suspension to be set to standard height. If the vehicle is at any
other height when the trailer is connected the air suspension will adjust to standard height and stay in that mode until
the trailer is disconnected.