Suspension Control ( Automatic - Electronic ): Description and Operation

AIR SUSPENSION

CIRCUIT OPERATION

The Electronic Air Suspension (EAS) is designed to maintain the selected vehicle height under varying loads. This is achieved by adjusting the quantity of air within the air springs located next to each wheel. It should be noted that the system is not intended to control the roll or dive of the vehicle whilst cornering or braking. The accuracy of height control achieved is sufficient to ensure that no additional driver controlled means of adjusting the headlamp beam is required to compensate for different vehicle loading conditions.

The system can operate in any one of five heights or modes: Access, Low Profile, Standard Profile, High Profile and Extended Profile. All heights with the exception of Extended Profile can be selected by the driver using the ride height switches on the fascia. When Inhibit is selected (indicated by the Inhibit switch tell-tale lamp being illuminated), automatic height changes between Standard and Low Profile are disabled; it is recommended that Standard Profile Inhibit mode is selected whenever a trailer is being towed.

The ride height of the vehicle is displayed to the driver by the LEDs in the ride height display adjacent to the ride height switches on the fascia. The LED for the current ride height is continuously illuminated whenever the engine is running. When a height change is taking place, the LED for the new target height flashes and the LED for the old height remains continuously illuminated until the new target height is reached whereupon the old height LED is extinguished and the new height LED is continuously illuminated.

It should be noted that if any of the side doors or the tailgate are open when the vehicle speed is less than 5 mph (8 km/h), all height changes are suspended until the doors and tailgate are closed. If a door has been open for more than 30 seconds, then the system will need "reminding" of the new height after the door has been closed. This condition is indicated by the LEDs for the old and new heights both being continuously illuminated.

Application of the Footbrake also causes any height changes to be suspended whilst it is pressed. If the Footbrake has been applied continuously for more than 3 minutes, then height changes are allowed to resume.

The ride height of the vehicle is correctly maintained only whilst the engine is running. To compensate for any changes in load after parking (e.g. driver or passengers getting out),the EAS system will lower the vehicle to the height of the lowest corner after the last door is closed. Furthermore, if the vehicle should develop a lean due to temperature effects or air leakage whilst parked, the EAS system is automatically re-powered every few hours to allow limited corrections to the height to be achieved.