Traction control, ABS and hill decent lights come on and stay on and now got a clunking noise coming from engine or underneath at the front

SOURCE: the "three amigo lights come

Excellent article on the ABS problem by John Robison at RoversNorth ..... 
 
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

SOURCE: abs light on in land rover

I have spent way too much money trying to get the 3 amigos to go out...ABS light, TC light and downhill descent. I have decided to try and ID the wires that go to those particular dash lights and cut them. I am tired of this ****. Landrover told me three different things that may cause this issue and told me to start with the least expensive one first! Go to hell, Landrover. I will NEVER buy another Landrover product. Which wires can I cut?

SOURCE: my abs tc and hill decent lights are staying on

unfortunately there is nothing that you can do, except take it to a land rover dealer to check with their tester, aftermarket code readers are not capable of reading land rovers. Hope this helps

SOURCE: In my Land Rover Discovery 2000, the ABS, traction

you've got a bad wheel speed sensor or corresponding tone ring. take it to a dealer. they'll hook it up to a computer and tell you which sensor or tone ring it is and give you an estimate. you only pay for the hour of diag.

SOURCE: 2000 landrover discovery td5 GS abs tc and hill

Suggests either Wheel Bearing, ABS Sensor Fault, or Shuttle valve. Best to get it to a dealer and on the computer for them to diagnose what exactly is wrong.