Air Suspension

Air Suspension

OPERATION

Power Distribution
Feed from the positive battery terminal (C0192) is supplied to fuse 26E, fusible link 10E and fusible link 11E (C0632) on an R wire. All are located in the Battery Junction Box (BJB).

Fuse 26E (C0570) provides a constant battery feed to the air suspension control module (C2321) on a PU wire. Fusible link 10E provides a constant battery feed to the air suspension relay, which is also located in the BJB.

Fusible link 11E (C0570) is connected to the ignition switch (C0028) by an N wire. When the ignition switch is in the 'ignition' position, current flows across the switch (C0028) to fuse 35P (C0582) on a Y wire. Fuse 35P is located in the Central Junction Box (CJB) (C0586) and provides an ignition feed to the air suspension control module (C0867) on an LGW wire. The air suspension control module (C2321) is provided a ground on a B wire.

Air Suspension Switch
The air suspension switch comprises two momentary (non-latching) switches; one to raise the ride height of the vehicle and one to lower the ride height of the vehicle. Operation of either switch will provide a ground from C2598 to the appropriate input on the air suspension control module: C0867-4 (lower); C02030-20 (raise).

The air suspension control module monitors the status of the non-latching air suspension switch (C0700) via two inputs. If a request is made to raise the ride height of the vehicle, a ground is momentarily provided via the switch on the BK wire to the control module (C2030). If a request is made to lower the ride height of the vehicle, a ground is momentarily provided via the switch on the BW wire to the control module (C0867). The air suspension switch ground is via a B wire (C2598).

Ride Height LEDs
The air suspension control module illuminates the appropriate LED on the center console switch pack (C0700) to inform the driver of air suspension system status.

The LEDs (C0700) have a common ground supply from the control module (C0867) on a BP wire. Illumination is as follows:
^ 'Off Road' LED, the control module (C0867) provides a feed on a BY wire.
^ 'On Road' LED, the control module (C2030) provides a feed on a BG wire.
^ 'Crawl' LED, the control module (C2030) provides a feed on a BN wire.
^ 'Access' LED, the control module (C2030) provides a feed on a BR wire.
^ To illuminate the 'Raising' LED, the control module (C2030) provides a feed on a BO wire.
^ To illuminate the 'Lowering' LED, the control module (C2030) provides a feed on a BS wire.

Height Sensors
A height sensor is fitted to each corner of the vehicle to monitor the ride height of the vehicle. The air suspension control module is connected to the height sensors as follows:

LH Front
The air suspension control module (C2321) provides a 5 V reference feed to the LH front height sensor (C1696) on an SG wire. The sensor returns a signal feed to the control module on an SO wire. Using pre-programmed information, the control module converts this signal into a height reading for the front LH corner of the vehicle. The control module also provides a ground path for the sensor on an SB wire.

RH Front
The air suspension control module (C2321) provides a 5 V reference feed to the RH front height sensor (C1697) on an SY wire. The sensor returns a signal feed to the control module on an SU wire. Using pre-programmed information, the control module converts this signal into a height reading for the front RH corner of the vehicle. The control module also provides a ground path for the sensor on an SR wire.

LH Rear
The air suspension control module (C2321) provides a 5 V reference feed to the LH rear height sensor (C1699) on an OY wire. The sensor returns a signal feed to the control module on an OR wire. Using pre-programmed information, the control module converts this signal into a height reading for the rear LH corner of the vehicle. The control module also provides a ground path for the sensor on an OB wire.

RH Rear
The air suspension control module (C2321) provides a 5 V reference feed to the RH rear height sensor (C1698) on an SY wire. The sensor returns a signal feed to the control module on an SU wire. Using pre-programmed information, the control module converts this signal into a height reading for the rear RH corner of the vehicle. The control module also provides a ground path for the sensor on an SR wire.

Air Supply Unit Relay
The air supply unit relay is located in the BJB and is provided a constant battery feed via fusible link 10. Operation of the relay (C0570) is controlled by the air suspension control module (C2321). To energise the relay, the control module provides a feed to the relay coil on an R wire, and a ground path via a BY wire. The energised relay (C0570) provides a feed to the air suspension compressor (C0780) on an NR wire. The compressor is located within the air supply unit and is provided a ground on a B wire.

The energised relay also provides a feed to the air suspension control module (C2321) via fuse 3E of the BJB (C0570) on an NR wire. This feed is used to inform the control module that the air supply unit is operational.

Air Supply Unit
The air supply unit is mounted on the LH chassis rail, and is operated by the air suspension control module as follows:

Pilot Exhaust Valve
The solenoid operated pilot exhaust valve is used to deflate the air springs when required. To energise the solenoid, and therefore release pressure from the system, the control module provides a feed on a BW wire and a ground via a BU wire.

Compressor Temperature Sensor
The air suspension control module monitors the temperature of the compressor to ensure it is within predetermined limits. The control module (C2321) provides a feed to the sensor (C0781) on a BY wire. By measuring the voltage returned on a BG wire, the control module can determine the temperature of the compressor.

Electric Motor Temperature Sensor
The air suspension control module monitors the temperature of the motor to ensure it is within pre-determined limits. The control module (C2320) provides a feed to the sensor (C0781) on a BO wire. By measuring the voltage returned on a BN wire, the control module can determine the temperature of the motor.

Reservoir Valve Block
The reservoir valve block is located on the LH chassis rail, adjacent the air supply unit. The air suspension control module is connected to the valve block as follows:

Reservoir Solenoid Valve
The reservoir solenoid valve controls pressure supply to and from the reservoir. Top operate the solenoid (C1689), the air suspension control module (C2321) provides a feed on a BW wire and a ground path via a B wire.

Pressure Sensor
The air suspension control module monitors the pressure in the reservoir and air springs via the pressure sensor located in the reservoir valve block. The control module (C2320) provides a 5 V reference feed to the sensor (C1684) on a YB wire and a ground path via a YK wire. By measuring the voltage returned from the sensor on an OS wire the control module can determine the pressure within the system.

Axle Valve Blocks

Front
The front axle valve block controls air supply to the front air spring damper modules. It contains a LH corner valve, a RH corner valve and a cross link valve. The air suspension control module (C2321) is connected to the front axle valve block (C2099) as follows:
^ A feed is provided to the LH corner valve solenoid on a BY wire.
^ A ground path is provided for the LH corner valve solenoid via a BG wire.
^ A feed is provided to the RH corner valve solenoid on a BP wire.
^ A ground path is provided for the RH corner valve solenoid via a BO wire.
^ A feed is provided to the cross link valve on a BW wire.
^ A ground path is provided for the cross link valve via a BU wire.

Rear
The rear axle valve block controls air supply to the rear air spring damper modules. It contains a LH corner valve, a RH corner valve and a cross link valve. The air suspension control module (C2030) is connected to the rear axle valve block (C2101) as follows:
^ The control module (C0867) provides a feed to the LH corner valve solenoid on a BY wire.
^ A ground path is provided by the control module (C0867) for the LH corner valve solenoid via a BG wire.
^ The control module (C0867) provides a feed to the RH corner valve solenoid on a BP wire.
^ A ground path is provided by the control module (C0867) for the RH corner valve solenoid via a BO wire.
^ The control module (C2030) provides a feed to the cross link valve on a BW wire.
^ A ground path is provided by the control module (C2030) for the cross link valve via a BU wire.