Land Rover Range Rover Electronic Arir Suspension Rover Manual

EAS - System Information Document
© Rover Group 1998Page 1 of 32
Range Rover
Electronic Air
Suspension
APPLICABILITYto 98MY
DATE OF REVISION03/06/98 

EAS - System Information Document
© Rover Group 1998Page 2 of 32
Introduction
The electronically controlled air suspension (EAS) system allows different
ride heights to be either manually or automatically selected. By changing the
volume of air in each of the air springs, the system maintains ride height and
quality regardless of load.
Four height sensors monitor vehicle height - one for each wheel. Data
received from each sensor by the electronic control module is used to
maintain, add or release air in...

EAS - System Information Document
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Table of Contents
INTRODUCTION.................................................................................................................2
TABLE OF CONTENTS......................................................................................................3
SYSTEM COMPONENTS...................................................................................................4
ELECTRONIC CONTROL UNIT...

EAS - System Information Document
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SYSTEM COMPONENTS
ELECTRONIC CONTROL UNIT (ECU)
The ECU, located under the right front seat on Range Rover Classic and the left front seat
on New Range Rover, communicates with the vehicle through a 35-cavity connector. Serial
data is available to retrieve fault messages and view real time data using TestBook. The
ECU is very reliable due to input and output overload protection.
BECM
NEW RANGE ROVER ONLY
The BeCM provides basic inputs to...

EAS - System Information Document
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HEIGHT SENSORS
The height sensors are chassis mounted potentiometers that are connected via a link to the
corresponding suspension member (e.g. trailing arm, radius rod). Each sensor modifies a
five-volt reference voltage to report the height information to the ECU. This information is
converted by the ECU to a digital format or “bits”. Height information is available through
TestBook as “bit counts”.
AIR COMPRESSOR
The electric air...

EAS - System Information Document
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PRESSURE SWITCH
The pressure switch is located in the valve block on both New Range Rover and Classic with
the exception of Classic with a VIN up to SA654292. The pressure switch on these models is
located on the air reservoir. The pressure switch contacts should be open at pressures
below 7.6 BAR (110 psi). The pressure switch contacts should be closed at a pressure of
10.1 BAR (154. Psi) A deviation of ±0.4 BAR (56 psi) is allowable for...

EAS - System Information Document
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AIR SPRINGS
The air springs are mounted in the same position as the conventional coil springs. The air
spring unit consists of a top plate, a rubber diaphragm, and a lower piston. Front and rear air
springs are not interchangeable. Upon failure the entire unit must be replaced.
NYLON AIR HARNESS
All pneumatic components are connected by nylon air lines to maximize corrosion resistance
and minimize fatigue failures. Each air spring and the...

EAS - System Information Document
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SYSTEM OPERATION
DOOR OPEN “WAKE-UP”
The system “wakes up” as soon as any door is opened. After all doors are closed, system
leveling could take place if any height sensors actual value differs from its target value by
more than ± 2 bits. The target value is determined by the lowest sensor input. If all the doors
are then closed, the delay relay will time out in twenty seconds. Height changes are inhibited
when any door (or tailgate on NRR)...

EAS - System Information Document
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SERVICE (RANGE ROVER CLASSIC)
The most useful tool available to repair any EAS problem is TestBook. The system is only
trying to make four sensors stay within a defined error range. Each rear sensor individually
should be within 2 bits of its target value while the front sensor values are averaged. See
TIB 60/02/94/US
The TestBook menu offers the following utilities:
CALIBRATE–This routine should only be performed when a height sensor or...

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RANGE  ROVER  CLASSIC  SERVICE  cont.
SYSTEM CALIBRATION
In an effort to adjust for variations between sensors and their locations on the chassis, it is
necessary to calibrate the vehicle’s body to specific sensor bit counts. This is accomplished
by supplying height measurements to specific height sensor outputs. At the start of the
routine, all existing sensor target values are over-written with new default values. This way a
consistent...