Theree Amigos.

I do not know if this is old news, but I founf this technical Information on the Three Amigos. It's dated 2004 but I have the same problem and it was very usefull.

http://www.nettechy.com/LRabsBulletin.pdf

TECHNICAL INFORMATION
Troubleshooting ABS/HDC/TC
Warning Lamp Illumination
No: 70/07/04/NAS
Ref:
Issue: 1
TIB CIRCULATE: Service Mgr Warranty Workshop Body Shop Parts
70/07/04/NAS TO X X X X X
? Land Rover 2004 Page 1
AFFECTED VEHICLE RANGE:
Discovery Series II XA900000 to XA999999
XA200412 and up
SITUATION:
WARNING LAMPS ILLUMINATED
Investigation of ABS, Traction Control (TC) or Hill Descent Control (HDC) warning lamp illumination
using T4 may reveal fault code "11,4: Shuttle Valve Switch (SVS) electrical failure." Because the
cause of an SVS electrical failure does not necessarily lie within the Modulator, additional diagnostic
routines may be required to define the problem further and ensure that the correct action is taken.
RESOLUTION:
PERFORM SPECIFIED TROUBLESHOOTING STEPS
NOTE: A number of ABS modulators have been returned to Land Rover with "no fault found"
when subjected to testing. This bulletin must be used as a guide to correctly diagnose a
concern before replacing an ABS modulator.
Should a customer complain about the illumination of the warning lamps and T4 investigate reveals
fault code "11,4 SVS electrical fault," use the information in this bulletin to correctly diagnose the
customer's concern.
PARTS/TOOL INFORMATION:
LRT 86-010/1...........Harness Repair Kit, Phase 2
DDW WARRANTY CLAIMS:
NOTE: "Prior con" requirment for ABS modulator units is removed with the publication of
this TIB.
DDW requires the use of causal part numbers. Labor only claims must show the causal part number
with a quantity of zero.
Description SRO Time
(Hours)
Condition
Code Causal Part
Diagnostic procedure for logged
shuttle valve switch failure 70.90.89/27 0.50 79
SRB101201
SRB101202
SRB101203
Normal warranty policy and procedures apply.
Material allowance is included in labor operation.
TECHNICAL INFORMATION
No: 70/07/04/NAS
Page 2 of 3
? Land Rover 2004
REPAIR PROCEDURE
NOTE: For connector views not detailed in this bulletin, refer to the GTR Discovery Electrical
Library.
1. Connect T4 to the vehicle and check for any logged fault
codes.
2. Locate the ground stud connection (C0561-1) located
on the radiator support behind the LH headlamp
assembly. (Figure 1)
3. Check that C0561-1 is undamaged and free of
corrosion.
4. If the ground stud is damaged or corroded, clean the
eyelet and stud and tighten the nut to 10 Nm
(7.5 lbf.ft.).
5. Check for continuity between the ground stud (C0561-1)
and C0500 connector on the ABS modulator body.
6. Move and flex the wire between C0561-1 and C0500 to
verify that there is no interruption in continuity.
CAUTION: Correctly crimped and soldered
wires are vital to an effective repair. GTR New Range Rover Electrical Library ? Introduction,
Harness Repairs outlines the methods and repair guidelines to be followed when performing
electrical repairs.
7. If there is no continuity or intermittent continuity when the wire is flexed, repair the damaged wire.
8. Disconnect and inspect the 13-pin connector at the ABS modulator (C0501) for moisture ingress and
corrosion.
9. Disconnect and inspect the 15-pin connector at the SLABS ECU (C0506) for moisture and corrosion.
CAUTION: Removing and repairing/replacing connector pins one at a time ensures that
thee pins are reinstalled in the correct position. Always following this procedure will protect
against incorrect wiring connections.
10. If moisture or corrosion is present in either connector, dry and clean the affected connector and repair
the corroded connector pins.
11. Connect an ohmmeter between pin 9 of the ABS modulator connector (C0501-9 yellow/green wire)
and ground.
NOTE: An assistant is required to perform the brake pedal application actions in the
following steps.
12. Monitor and record the change in resistance as an assistant very slowly depresses the brake pedal.
13. Check results against the values shown in the resistance table below:
Approximate pedal
position
Minimum
resistance
Maximum
resistance
No travel 2555 Ohms 4088 Ohms
Partial travel 1533 Ohms 2554 Ohms
Full Travel 511 Ohms 1532 Ohms
Figure 1
LOCATION: Behind LH Headlamp
Air intake box removed for visibility
TECHNICAL INFORMATION
No: 70/07/04/NAS
Page 3 of 3
? Land Rover 2004
14. If the resistance is outside the minimum and maximum values shown in the table, replace the ABS
modulator.
15. Connect an ohmmeter between pin 6 of the SLABS connector (C0506-6 yellow/ green wire) and
ground.
16. Monitor and record the change in resistance as an assistant very slowly depresses the brake pedal.
17. Check results against the values shown in the resistance table below:
Approximate pedal
position
Minimum
resistance
Maximum
resistance
No travel 2555 Ohms 4088 Ohms
Partial travel 1533 Ohms 2554 Ohms
Full Travel 511 Ohms 1532 Ohms
18. If the resistance is outside the minimum and maximum values in the table, check for continuity
between pin 6 of the 15-pin SLABS ECU connector (C0506-6) and pin 9 of the ABS modulator
connector (C0501-9 yellow/ green wire).
19. If there is no continuity or intermittent continuity when
the wire is flexed, repair or replace the damaged wire.
20. If the resistance is between the minimum and maximum
values, check for continuity between pin 12 of the 18-
pin SLABS ECU connector (C0504-12 - black wire) and
ground C0362-1 located high on the LH inner fender
within the passenger compartment. (Figure 2)
21. If there is no continuity or intermittent continuity when
the wire is flexed, repair or replace the damaged wire.
22. Check for continuity between pin 3 of the 15-pin SLABS
ECU connector (C0506-3 black/slate wire) and ground.
23. If there is no continuity or intermittent continuity when
the wire is flexed between C0506-3 and ground, check
for continuity between pin 3 and pin 8 of ABS modulator
connector (C0501-8).
24. If there is no continuity or intermittent continuity when
the wire is flexed between C0506-3 and
C0501-8, repair or replace the damaged wire.
25. If there is continuity between C0506-3 and C0501-8,
replace the modulator.
26. If there is continuity between C0506-3 and ground,
replace the SLABS ECU.
27. Disconnect T4 from the vehicle.
28. Road test the vehicle to ensure the warning lights are
not illuminated.
29. Re-connect T4 to verify that the fault is now historic.
30. Clear all logged fault codes.
Figure 2

Theree Amigos. II.

More info on 3 Amigos.

http://www.robisonservice.com/articles/ABS.pdf

Welcome to the techie column for the Fall edition of
the Rover News. In this column, we?re going to look
at some of the common problems with the antilock
brakes on Discovery II models. The Discovery II electronic
braking system, called SLABS (self leveling anti
lock braking), is made by Wabco of Germany. Wabco
is a subsidiary of American Standard, a company better
known to the public for toilets than brakes. In the
automotive field, Wabco specializes in braking and
suspension systems for trucks. According to the company,
two out of three commercial vehicles with
advanced braking systems are equipped with Wabco
products.
The Land Rover system includes four-wheel
antilock braking, hill descent control, and four-wheel
traction control. The SLABS control unit also controls
the self-leveling suspension, if the vehicle has that feature.
The Discovery air suspension is also a Wabco
product. As an aside, Wabco air suspension is also
found in the new Audi A6 and the Mercedes CLS.
One of the most common ABS questions I
hear is, Why do I see the ABS, Traction
Control, and Hill Descent lights coming on?
All three of those systems share a common set of
core components. The wheel speed sensors, the hubs,
the modulator, the controller, and other parts serve all
three systems. So a fault in any one of them will cause
a problem in the other two. It is actually rare to have
a fault that would only disable one of the three systems.
99% of the time, if one is affected, they all are.
To see what?s wrong, you will need to connect a
Land Rover test system and read the faults. These systems
are not OBD II compatible, so a generic scanner
won?t talk to them. At Robison Service, we use the T4
or Autologic tools for this work.
The most common faults are wheel speed
sensor faults. The wheel speed sensors in a Land
Rover are coils that sense the motion of a toothed
wheel that?s a part of the wheel hub. The rotation of
the wheel induces a sine wave signal in the sensor
whose frequency is proportional to the speed, and
whose amplitude increases with speed from 0.5 volts
to more than 5 volts.
If your Rover has a speed sensor fault, there are
two paths to repair. The first is to replace the entire
hub on the affected corner. This is the approach
favored by dealers because the toothed wheel ? called
a reluctor ring ? and the actual sensor are both part
of the hub. The reluctor can get damaged by rust or
corrosion, and it can also get damaged by a bad wheel
bearing. The only way to service it is to change the
hub.
As of this writing, hubs (front-RND646 / rear-RND694)
cost around $400 and take about three hours to
change.
The sensor can be removed from the hub fairly
easily. If you remove your sensor and look inside you
should be able to see if the reluctor ring is damaged.
The reluctor ring can get damaged if the wheel bearing
gets loose. It can also get damaged by corrosion.
That?s especially true for Rovers that run on beaches.
If you see reluctor ring damage, or corrosion, or if the
hub has any free play at all ? you need a complete
assembly. If there is no damage, you may be able to
fix the vehicle by changing the sensor (front-RN292 /
rear-RNH293) alone, a $100 part that?s less than an hour
to swap.
The path you choose should be determined by
examination of the reluctor via the sensor hole. If the
hub looks good, there?s an ?8 or 10? odds that a sensor
alone will fix your problem.
Every now and then you will see a Rover that has
wiring problems, usually at the connector between ABS
sensor and body. Always pull it apart and look for
corrosion.
The next common fault in these systems
is called shuttle valve failure. The shuttle valve
is a part of the brake modulator ? that big thing in the
location where a master cylinder would be. The modulator
incorporates the functions of an ABS servo and
a brake master cylinder into one unit.
If you have shuttle valve problems, you will see
the three warning lights on the dash and there will be
one or more stored faults for shuttle valve failure.
Land Rover has a test procedure to determine if these
faults result from a failure in the modulator or if they
are caused by wiring troubles in the ABS harness or
grounds. Unless you have corroded grounds and
cables, your trouble is probably in the modulator.
Until now, this problem was addressed by
replacement of the brake modulator (RNH082). That?s a
$1,500 part. As you can imagine, shuttle valve failure
produced a lot of unhappy owners and Land Rover
finally listened up and developed a fix.
As of March 2006, Land Rover sells a shuttle
valve repair kit for under $100. You will have to
remove the modulator and flip it over to install the
valves on a workbench. Removal of the modulator,
replacement of the valve, and refit to the vehicle takes
three hours or so.
This shuttle valve repair is a huge improvement
over the former method of addressing this problem.
The part number for the repair kit is (SW0500030).
If you buy it from a dealer you may also want to ask
for the March 2006 bulletin that gives test and installation
instructions.
Another common problem is a mushy
brake pedal. In my experience, the only explanation
for a mushy pedal is improper bleeding procedure.
Bleeding a Discovery II takes two people and the Land
Rover test system, and it takes the two of them a bit
over half an hour. You need the tester to operate the
pump and valves to make sure all the air is purged
from the modulator.
If you are paying for this service, expect a labor
bill in the range of one and a half hours and $20-30 of
brake fluid. If you are not at a dealer, make sure they
use the correct Castrol LMA fluid. Don?t even start this
process unless the shop has a tester to run the pump
and valves. You could bleed brakes in the field without
one in an emergency, but there is no way to get a
really good pedal without cycling pump and valves.
There is no shortcut for this job. You need two
people and the Land Rover tester.
We see quite a few stop lamp circuit
problems. The usual way this problem manifests
itself is a truck that won?t shift out of park. Discovery
II models have an interlock that prevents shifting out
of park unless the brake is pressed. So, if the brake
light circuit fails, the car won?t go into gear.
If that happens to you, the first step is to check
the stop lamp fuse. We?ve seen several trucks where
the stop lamps were fitted wrong, or the contacts corroded,
and the fuse blew. Also check the trailer connector,
if your Rover has one. A short there can pop
fuses.
If the fuses are good, you should check the stop
lamp switch. It?s located above the brake pedal. If
you are stuck somewhere, it is possible to get out of
park by jumping the switch temporarily with a paper
clip.
Finally, you should check your Rover to
see if the brake modulator recall was done. If
it was, you should have a B148 sticker on the radiator
support. All Discovery II models built before spring of
2003 are subject to the recall. Land Rover found the
caps on the ABS modulator were cracking under heavy
off-road use. Therefore, they came up with heavier
replacements. The caps are a quick bolt on installation.
If you are near a dealer they will do this for you
at no charge. If you can?t get to a dealer, or you?re
outside the USA, the part number for the kit is
SWO500010K. Complete illustrated instructions can
be found in the B148 recall bulletin, available from
your dealer with the kit.
This recall does not involve any hydraulic system
disassembly, so the brakes won?t feel or act any differently.
The heavier caps are plainly visible on top of the
modulator. Once you see them, you?ll be able to tell it
was done.
Note: Recalls should always be done at your
dealer so they can be properly recorded. Only do this
yourself if you absolutely can?t get to a dealer, or if
your Rover is not eligible because it?s a rebuilt salvage
vehicle.
Final notes:
Remember that you can access all of the most current
service information, including workshop manuals,
electrical manuals, recall notices, and service bulletins
on Land Rover?s web site,
http://www.landrovertechinfo.com
www.landrovertechinfo.com
If you look on the Land Rover site under ?training?
you will find the introduction to the 1999
Discovery II. That training book has a 23-page
description of the Wabco electronic system.
You can also find quite a bit of information ?
including reprints of many of my articles - on my web
site, http://www.robisonservice.com www.robisonservice.
com > Service > Land Rover > advice and articles
Wabco is online at http://www.wabco-auto.com
www.wabco-auto.com
If you have questions or issues you?d like discussed
email: robison@robisonservice.com
________  ________
ROBISON ON ROVERS
Repairing ABS problems in the Discovery II
By John Robison