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Air Springs
The air spring is made from a flexible rubber material. It
forms an air tight cavity which provides the calculated spring
rate required for the sport wagon.
As the spring compresses downward the bottom edge of
the rubber material rolls along the vertical surface of the
base mount cylinder.
Air is added or removed from the air spring through its top
port. The top port of each spring is connected to a reser-
voir and the air supply pipes. The reservoirs are required to
hold additional air due to the compact design of the springs.
Rear Axle Level Sensors
Hall effect sensors are mounted on the left
and right sides of the rear suspension for ride
height detection. They are pivoted by a cou-
pling rod through the rear axle swing arms.
The hall sensors produce a varying voltage
input to the control module as the suspension
height changes.
If the vehicle is equipped with Xenon head-
lights the right side sensor contains an addi-
tional sensor for the automatic headlight level
adjustment system.
Warning Display
If the system is faulted and off-line or set in the transport mode, the following is displayed:
High Cluster: A message is posted in the high cluster matrix display.
E39 Features 07
37
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Special Operation Mode
• Assembly Line Mode (New control module)
The assembly line mode refers to control module manufacturing. New control modules
are stored in a deactivated state. The control programming is not active and must first
be ZCS encoded.
After installing a replacement control module, it must be coded using the DIS or MoDiC.
The instrument cluster fault display will remain illuminated until the control module is
coded.
Control Interrupts
Cornering
To prevent unnecessary suspension adjustments while driving through corners, a “control
interrupt” is built into the system. Above 30MPH the control module monitors the left/right
ride height sensors for a difference of 30mm. Exceeding this difference will put the system
into a control interrupt and no adjustment will take place. The control interrupt last for a
duration of 5 minutes.
Vehicle Lifting
The ride height control is interrupted when the vehicle is raised on a lift or with a jack. The
system monitors the ride height sensor inputs and when the height limit of 90 mm is
exceeded, the control is switched OFF until the vehicle is lowered again.
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EHC Service Information
Diagnosis / Coding
• The EHC control module is connected to the diagnostic link. The EHC control module
activates the fault display in the instrument cluster to alert the operator of the off-line sta-
tus of the system. The EHC control module stores up to three electrical/electronic
faults.
• Diagnosis/troubleshooting of EHC is carried out using the fault symptom troubleshoot-
ing program of the MoDiC or DIS. The EHC system has an extensive diagnosis program.
• Replacement control modules are shipped in the factory mode. The control modules
must be ZCS encoded using the DIS or MoDiC to activate the operating parameters.
