Introduction
Rule #1: Get to it Before the ECU goes into Fault
Mode:
Driving Home in EAS Fault Mode
Restoring Operation While in Fault
Mode
Leak Detection
Air Hose Leak Repairs
Compressor Field Repair
Air Spring Replacement in the Field
Temporary Repair with Wood Blocks
Height Sensor Replacement or Repair
Manual Operation if a Fault Occurs
Depressurizing the System
Disabling the EAS
Photo at right by Chris Crompton: Awkward situation when EAS drops to bump stops in the field.
IntroductionCAUTIONARY NOTE: The EAS system uses air at 10 bar (150 psi) which is a very high pressure. Be careful when doing any operation on it; the air should be removed from the system before repairs are carried out. See notes under "Depressurizing the System".
Rule #1: Get to
it
Before
the ECU goes into Fault Mode
If an EAS problem happens in the field and it looks like one you
might
be able to repair, it is important to do the repair before the
ECU
detects the problem and goes into the "hard fault" mode ("EAS FAULT"
message
on the message center, EAS warning light on, and all EAS lights lit up
on the height control). Once it is in this mode, it can only be reset
by
the dealer's Test Book, even though you may have fixed the cause of the
fault. This is particularly the case with 1995-98 models with the GEMS
engine control system which has non-volatile memory. On 1999-2002
models
the Bosch electronics uses volatile memory, but the EAS computer faults
still cannot be reset by disconnecting the battery -- this fact was
confirmed
during a recent incident on a 2000 model by alert reader John
Angott. (Please
email me
to let me know if you have found any way to reset it).
If you are in an awkward spot not suitable for repair work and want to delay the evil moment when the ECU goes into this annoying fault mode, crack open a door or tailgate as you drive along or unplug the EAS timer relay, a small black box under the left front seat. Either of these actions should freeze up the EAS and put it into a state of suspended animation until you get to a suitable place to do your repairs. If you open the tailgate, also remember to open your windows to prevent asphyxiation. (Please email me to let me know if you have tried these or any other techniques and whether they worked -- sorry I can make no guarantees!!).
Update November 2003: I recently had occasion for (another) practical test when my air compressor went on the blink. After pumping up the system with air again, I disabled the EAS by unplugging the EAS delay timer under the seat. I then drove the car for a couple of days with no problem -- a "35 mph max" message was displayed on the dash but it did NOT go into hard fault mode. I was able to effect a repair after a couple of days and the system reverted to normal. I previously thought that removing fuse 44 was also an acceptable option, but John Hudson recently reported that doing this sent his into hard fault mode.
Driving Home in
EAS Fault
Mode
If the problem is not fixable in the field, but you have only
suffered
loss of air from the tank, failure of the compressor or some other
problem
that leaves the car at normal ride height, you can merrily continue the
journey or drive to the nearest dealer at your leisure. In this case,
as
an extra precaution, I would unplug the suspension delay timer relay
under the front left seat to completely disable the system. This will
prevent the suspension ECU
getting bright ideas about lowering the suspension to the bump stops or
doing any other adjustments that you don't want. Of course, if your
valve
block is getting old like mine, the air will eventually leak out of the
springs through the valve block anyway, but that might take a day or
two
-- even longer if your system is newish or in good shape. Even then you
might be able to pump ut up again with one of the techniques suggested
below in the Manual EAS Operation section.
If you have ended up in in hard fault mode with one or both ends of
the vehicle on the bump stops, do not panic. You can
still
drive merrily home or to the nearest dealer, even if that is a long way
away. The edict in the owners manual about not exceeding 35 mph under
these
conditions is doubtlessly put there to protect Land Rover from warranty
or liability claims -- the ride on the bump stops is a bit bumpy but on
good smooth highways and freeways I have been able to keep up with the
traffic flow quite well, at speeds up to 70 mph. If you are lucky and
only
one end of the vehicle is on the bump stops, as happens when a spring
fails,
the ride is correspondingly better. When my front end landed on the
bump
stops after the spring blowout, I had to drive 450 miles to the dealer
-- I did it in 7.5 hours. When my air tank leak put both front and rear
ends on the bump stops I drove over 100 miles to the nearest dealer
without
much discomfort and still kept up with the traffic.
 |
|
| EAS ECU connector C117 is
located under the front of the left front seat (4.0/4.6). To access it,
remove
the seat base trim panel and the black plastic ECU dust cover. |
Photo of the connector unplugged from the ECU, showing which pins to jumper to operate the compressor. In this photo, the cable enters the connector from the left. |
A can of proprietary leak detector in a spray can can be purchased
from the dealer, or you can put a home made solution of soapy water on
the suspected spots (usually where the air lines enter and leave the
valve
block) and watch for bubbles.
Leaks in the air hose lines
A hose repair kit is available from Land Rover to fix leaks in the
air lines (part number STC8580 is the connector alone, or a kit is
available with the connector plus about 10 feet of air line). The
repair kit is a 6 mm one, which fits the main air lines
connecting the air tank, valve block and air springs. It does not
repair
the short 4 mm and 8 mm lines used for the exhaust and the air dryer. I
have not yet heard of anyone actually developing a leak in one of these
hoses, but it is nice to know the
repair
can be done. According to Technical Service Bulletin 0027, leaks in the
rear exhaust assembly have been known to generate enough heat to
destroy the integrity of either the rear air spring lines or the
reservoir line (see photo at right from the Technical Service Bulletin
indicating the areas at risk). Unlike the situation i the early days of
4.0/4.6 Range Rover ownership, spare hose line is now inexpensively
available from Rover Renovations.
Leaks where the hose enters the valve block
More commonly, a leak will occur where the hose enters the valve block
or the spring, but this is unlikely to be a bad enough leak to bother
fixing
in the field. However it can be repaired at leisure by replacing the
rubber
"O" ring in the connection. After depressurizing you can press in the
collet
and pull out the hose from the offending connection. Then fish out the
"O" rings with a crochet hook or a bent wire with a rounded end so as
not to damage the valve block O-ring seat.
Replacement O-Rings
The "O" ring did not used to be a standard Land Rover part (they prefer
you to
replace the whole $800 valve block). One dealer mechanic I talked to
had the dealer buy them for
him.
Nowadays, you can buy them as official parts (for part numbers see the valve block page), or more
conveniently, buy a complete set of O rings for the valve block from Rover Renovations
for under $20!
In an emergency you can even get the O rings from a hardware store.
When Ron Beckett was
getting
leakage from the main airline from the tank into the valve block (a
fairly
common leak) he measured the "O" rings and found they were 6mm I.D. and
2.5mm ring thickness. Terry
Mueller found that in
backward countries like the US that have not switched to the metric
system, standard O rings with 1/4 inch inside diameter and 7/16ths OD
work perfectly. This makes sense as
the air lines are 6mm OD. He used a micrometer to check the ring
thickness
and a 6mm drill shank to check the ID - it was a perfect fit.)
Ron found the crochet needle as suggested in the workshop manual was
perfect
for removing the O-rings.
For more details on the valve block see the Valve
Block page.
 |
A comparison of the O-ring from Ron Beckett's rear air spring (normal O-ring) vs the leaking O-ring from the valve block. Note the latter (left) is patterned from being pressed against the collet for many years. The other side looks like a normal O-ring. These rings are 6mm ID and 2.5mm ring thickness. |
If the compressor is working but will not get up to operating
pressure (and the problem is not due to air escaping somewhere else),
you can fairly easily take the compressor apart and "rebuild" it by
replacing the teflon seal on teh piston with a jury-rigged part, made
for example from the bottom of a plastic 35 mm film container. Details
of this and other temporary ways of fixing the seal are supplied on the
Compressor Field Repair Page.
Another possible fault on the compressor that happened to me was
failure of its thermal cutout switch, (the
third and thinnest
lead, colored orange, emerging from the pump motor body),
making the ECU think it is overheated. I just grounded this wire so the
ECU would think the pump was not
overheating, and continued on my way.
See also the Compressor Diagnosis &
Replacement Page for more diagnostic assistance.
Air Spring Replacement in the Field
With the appearance of inexpensive aftermarket air springs, it is
now practical to carry spares, so failure in the field is no longer an
expedition-killing event. You have two options -- one is to replace the
bladder only, keeping the ends or pistons in place. The
bladder is now available inexpensively from
most Rover parts suppliers, or direct from the US-based aftermarket
manufacturer, Arnott
Industries.
Arnott's front bladder
($91)
was originally specified for both front and rear, so should fit both in
a pinch (although Arnott now specifies a new longer $107
bladder
for the rear), so you can carry a single bladder for a repair to any
spring. Rover Renovations
now lso sells the replacement bladder at even lower prices. For more
information on suppliers see the Air
Spring Replacement page. The second option is to replace the whole
spring assembly; this is not much more expensive and is much quicker
and easier than the "bladder-only" replacement operation. In either
case, stop and do it before
the EAS goes into hard fault mode; see Rule
1 above.
Field Replacement of Complete Spring
Carrying complete spare spring assemblies
-- one for the front and one for the rear -- makes for a more bulky
"spare parts" box, but a much faster field
repair (faster than changing a broken coil spring). Procedures for
changing an air spring are fully described on the "Air Spring
Replacement" page, but keep in mind that these and the official
instructions assume access to a normal garage with one or two
floor jacks and a set of axle/chassis stands. Without these facilities,
you can't get the wheels off while supporting the chassis. Having had
to replace an
air spring in the field without these luxuries on hand, or even any
rocks in sight to rest the chassis on, I offer the following modified
shortcut
method based on hard experience, leaving the wheels on.
John's Field Replacement
Shortcut
1. Open rear hatch or a door to immobilize the EAS computer, and
jack up the chassis
at the affected corner to about "High" level or a bit higher.
2. Release clips at top and bottom of spring**, then release air line
(push collar with screwdriver
while yanking on air pipe). Careful of air blast.
3. Manoever old spring out and replace with new one. For front spring,
lower jack enough to make spring top and bottom
connect to fixings without bending off kilter. Attach clips and shove
airline into fitting.
4. For rear spring, leave jack high for access. Insert new spring in
top mount, supporting its lower end as needed to bed top evenly. Insert
top clip and air line, then insert lower end of spring in mount and
insert bottom clip.
5. Lower jack so corner being worked on is below normal. Start engine,
shut doors and allow vehicle to pump itself up off the jack.
Temporary
Repair with Wood Blocks
If you are in an off road situation when the failure occurs and need
more clearance than available when the system drops to the bumpstops,
you can do as Chris Crompton did when his failed in the Abu Dhabi
desert -- just jack up the car and tape some wood blocks (or any other
material that is strong enough) under the bump stops! (See photo at
right). For full details on this technique see the Air Suspension Field Repair with Wood Blocks
page.
Height Sensor Repair
or
Replacement
If a height sensor appears to have gone bad in the field (eg by the
ingress of water), Bill O'Brien reports that you can remove,
disassemble
and clean them. He suggests prying the back off and cleaning with
carbon
tet or volume control cleaner from Radio Shack. Reseal the back with
silicone. Peter Sanders
checked his height sensors on his (94 Classic) RR
and found that one of them seemed to have what sounded like
"grit" inside. Because of this and the fact that the relays were
being operated on/off quite rapidly he decided to take the sensor
apart. He carefully took the back off to examine the "innards",
and found they are very well made and do appear to have a very long
life. They are made with two potentiomer "circuits", so they can
work on either side of the vehicle. Thus, you can double their
life span if you do as Peter did and swap them from side to side.
(I am not sure if this is the case though with the 4.0/4.6 sensors --
please email me if you
have taken one apart.
Manual Operation
if a
Fault
Occurs
(For more information on this topic please see the Manual Suspension Pump-up page)
It is possible to operate the EAS manually with jumper wires in an
emergency. It is also possible to get the compressor to run using
jumper wires. For details of these procedures see the Manual
Suspension Pump-up page.
A second approach was also successfully tried by Mark Hudson when his compressor needed replacing (but before the system went into hard fault mode). He found that "Before I replaced the compressor I was able to air up the suspension using my compressor at home. I simply disconnected the compressor air hose and slipped a plastic tube over it and clamped it the best I could. Air leaked out like crazy, but I was able to air up the bags and they stayed up due to the back-flow preventer valve". (Note if you have the same problem as Mark did while in the field, you can temporarily "rebuild" the compressor by replacing the seal on its piston with a jury rigged part; see the Compressor Field Repair Page).
Another manual option is to instal an EAS
override system prior to
venturing
out. Mike Ferguson added standard tire valves to each of the
4 air lines, so he
can manually pump up the suspension using any standard tire pump or air
supply. Details of his modifications appear on the "Manual
Suspension Pump-up page. Airbag
Man in Australia (worldwide shipping) supplies an inexpensive Range
Rover Safety/Emergency Kit with isolation valves, inflation valves,
tubing, and instructions that allows you to pump up the springs
individually from any tire pump. Another manual option is to instal an
EAS
override system prior to
venturing
out. The Black
Dog Air Valve Conversion Kit available from MotorcarsLtd also
includes
standard
air fittings that allow you to plug a regular tire pump in to the air
line
for any spring and pump it up to the desired height. More recently, the
Manual Air Recovery System (MARS) allows the
same functionality for a lower cost.
The manual advises depressurizing the system before replacing
components
such as springs. Their procedure for doing so requires the Test Book.
However
if you are in the field with a blown air spring, obviously the spring
itself
will already be depressurized. You can depressurize the air tank by
SLOWLY
unscrewing the drain plug -- it has a notch in the threads so when it
is
part way out it lets the air escape without firing the plug out like a
bullet.
As Dennis Altman points out, an alternative method is to de-pressurize the system using jumpers. To do this, access the main EAS ECU connector under the front of the driver's seat -- see the section on Manual EAS Valve Activation. Just connect all the valves (pin 9,10,11, 26, 27 and 28 on the she'll settle down nicely, and dump the tank for you.
For many repair operations you don't want the suspension to be
adjusting
itself up and down while you work on the vehicle. Classic air sprung
models
have a disable switch under the seat, but this is lacking on the
4.0/4.6.
On these models, the following options are available for disabling the
system:
1. Leaving a door or the tailgate open effectively freezes the
suspension
2. Unplug the air suspension delay timer, a small black box that looks
like a large relay under the drivers seat.
See Air Suspension Disabling
on the air spring replacement page.
More EAS Information
Range Rover
Suspension Details and Mods
Replacing an Air Spring
Air Spring Replacement
(Bladder
Only)
Arnott Generation
III Air Spring Upgrade: firmer on hwy, softer off road and more
travel
Clearing EAS Faults using your
Notebook Comouter
Compressor Diagnosis and Replacement
Compressor Rebuild Procedure
Compressor Field Repair / Temporary
Rebuild
EAS ECU Interface and Diagnostic Cable
Details
Valve Block Details and Repair
Disabling the EAS
Emergency
Bypass of EAS
Extended
Profile Selector
Lifting the Air Suspension
Manual
Pump-up of Air
Suspension
Parts Sources for EAS Components
Repair Details
Replacement
with Coil Springs
Restoring Normal EAS Operation in Fault Mode
After Repairing the Cause
Rover Renovations
(low cost US supplier of Range Rover EAS components and parts)
Low cost and generic parts sources
(including
suspension parts)
Strutmasters
US maker of alternative air suspension parts; low cost supplier of
Range Rover air spring bellows.
Airbag
Man (Low cost Australian supplier of RR air suspension
springs, compressors, parts. Worldwide shipping).
Arnott
Industries (makers
of air spring bladders)
Andy
Cunningham's Air Suspension Operation Page
Andy Cunningham's
Air Suspension Troubleshooting page
Mechanical and Electrical Upgrades
Page last updated April 2007
