System Operation

ENGINE RUN OPERATION
The system will compensate for load addition or removal where :
a. the trunk and doors are closed
b. the engine speed exceeds 600 RPM

ENGINE OFF OPERATION
After passengers or other loads are removed from the vehicle the system will correct vehicle attitude after:
a. the trunk and all doors are closed
b. the ignition switch is in the "OFF" position.

GENERAL OPERATION
With the vehicle at "customer height", the height control solenoids at all four air springs are closed (de-energized). Air is trapped in each air spring.

When a load is added to the trunk area, for example, the rear height sensor signals a "low" condition to the Air Suspension Control Module (ASCM) mounted in the trunk. If all conditions required for safe operation exist, the compressor relay will be pulled closed, commencing compressor operation. Both rear height control solenoids are opened, allowing system pressure to push air into each rear spring. The rear of the vehicle now begins to raise as the compressor continues to run. When the signal from the rear height sensor located on the right rear shock Indicates customer height has been reached, the ASCM will close both rear height control solenoids and shut oft the compressor.

When the load is removed from the trunk (to continue this example), the rear height sensor signals a "high" condition to the ASCM. The exhaust solenoid at the compressor is opened, and both rear air spring solenoids are opened. Air from both rear air springs is allowed to vent through the drier to atmosphere via the vent solenoid. The rear of the vehicle lowers until the rear height sensor signals customer height. At this time both rear height control solenoids and the compressor exhaust solenoid are closed.

TERMINATION OF HEIGHT CORRECTION
The ASCM module will not allow height correction if one of the following occurs:

a. Door or deck lid open.
When one or more doors or the deck lid is open and the vehicle speed is less than 5 mph, the ASCM shall suspend height correction. Height correction will resume after the appropriate bus messages indicate that the doors and deck lid are closed and vehicle speed is above 10 mph.

b. Acceleration
When the throttle is wide open (WOT), the controller will suspend height correction.

c. Braking
When the brake switch is closed (brakes applied), the ASCM will suspend height correction. Height correction will resume 5 seconds after the bus indicates the brake switch is open (brakes off)

d. High Speed Cornering
When the right front and left front height sensors differ by more than one region, and the vehicle speed is greater than 10 mph, the ASCM will suspend height correction. Height correction will resume 5 seconds after the front sensors no longer differ more than one region, or when the vehicle speed is reduced to less than 10 mph.

e. Throttle Position Sensor Failure
When the throttle Position Sensor fails the ASCM will suspend height correction.

f. Charging System Failure