Item name | Spare part number | Description |
1 | - | Air suspension control unit |
2 | - | Connector C2321 |
3 | - | Connector C2320 |
4 | - | Connector C2030 |
5 | - | Connector C0867 |
The air suspension control unit is located behind the instrument panel on the 'A' pillar on the driver's side. The control box is attached to the 'A' post with one screw and two plastic clips.
Calibration
The calibration procedure is carried out using Land Rover approved diagnostic equipment, which is used to read the position of each corner of the vehicle and write the parameters to the memory of the control unit. Recalibration is only required if the air suspension control unit is removed or replaced, the height sensor is removed or replaced, or the suspension arm to which the sensor is attached is removed or replaced. If a removed height sensor is reinstalled, a calibration must be performed to ensure system integrity.
In case of removal or replacement of the compressor block, receiver, valve block, shock absorber module or air line, system calibration is not required.
Inputs and inputs
The air suspension control unit has four connectors for signal input and output.
The air suspension control unit receives signals from other vehicle systems via the CAN bus. The system uses data such as longitudinal acceleration, lateral acceleration, steering angle and wheel speed to control the suspension under various driving conditions.
If one or more of these input signals is missing or fails, the system reacts differently: for example, if there is no or error signal from the steering wheel angle sensor, the air suspension control unit defaults the signal value to zero, which can lead to unnecessary leveling operations body.
Compressor unit relay
The compressor unit relay is located in the battery junction box in the engine compartment. The relay is directly connected to the battery via a 10E fuse (60A). The relay coil is connected to the air suspension control unit and is controlled from it. The air suspension control unit uses a relay to control the operation of the compressor.
When the compressor needs to be turned on, the air suspension control unit energizes and "mass" on the relay winding, which leads to the closure of the relay contacts. Due to this, the voltage of the battery through the fusible link and the relay is supplied to the electric motor of the compressor unit and the compressor.
In addition, battery voltage is supplied from the relay through a cable splice to the air suspension control unit and is used as a signal for the operation of the compressor unit.
System bans
There are a number of conditions in which a change in altitude is undesirable. To account for these conditions, certain system inhibitions are programmed into the air suspension control unit. If any of the following conditions are met, the air suspension control unit will suspend the height change and correction.
Compressor
The compressor is equipped with temperature sensors that protect it from overheating. If the compressor temperature exceeds the set values, the air suspension control unit disables the operation of the compressor. These limit values are shown in the following table.
Compressor head temperature sensor
Climb | Receiver | |
Termination of work | 140°C (284°F) | 130°C (266°F) |
Beginning of work | 120°C (248°F) | 110°C (230°F) |
Compressor brush holder temperature sensor
Climb | Receiver | |
Termination of work | 140°C (284°F) | 130°C (266°F) |
Beginning of work | 120°C (248°F) | 110°C (230°F) |
Turn
When the air suspension control unit registers a centripetal acceleration of more than 0.2 g, it inhibits any changes and height adjustments. The inhibition is maintained until the centripetal acceleration falls below 0.15 in. The air suspension control unit receives the centripetal acceleration data from the lateral acceleration sensor integrated in the ABS yaw sensor via the high speed CAN bus.
Fast acceleration
When the air suspension control unit detects rapid acceleration (more than 0.2 d), it prohibits any changes and height adjustments. The inhibition is maintained until the acceleration falls below 0.15 in. The acceleration is calculated by the air suspension control unit from the vehicle speed signal received via the high speed CAN bus.
Rapid deceleration
When the air suspension control unit detects a rapid deceleration (less than -0.2 d), it prohibits any changes and height adjustments. The inhibition is maintained until the deceleration exceeds -0.15 ind. The deceleration is calculated by the air suspension control unit from the vehicle speed signal received via the high speed CAN bus.
Car jacking
The air suspension control unit inhibits any changes and height adjustments if it detects that one of the corners is lowered too slowly for more than 1.2 seconds. Slow lowering of the corner is considered a sign that a jack is placed under it. In this case, the angle height does not change when air is released from the elastic pneumatic element, since the jack acts as a mechanical support. The ban is maintained as long as any of the following conditions are met:
- The air suspension switch is set to the up or down position.
- Vehicle speed exceeds 3 km/h for more than 45 seconds.
Door opening
When any door is opened, the air suspension control unit stops any height changes. Body leveling continues with the door open by maintaining the height of the body in the event of a change in load.
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