Thread: ABS sensor, TC, HD fault

try cleaning the rotor assembly this will still involve removing the hub it may have metal filings giving a false reading and did you keep the old speed sensor??by the sounds of it you have gone to a dealer to get it fixed?

You've got no option but to keep repairing it. Rego & no doubt insurance are at risk. In NSW anyway, I'm told rego checks expressly include ensuring ABS works as it should - self check at startup, & the light going out after a few metres.

Removing the bulb isn't an option

Its a problem all ABS landrovers seem to have. My lights have reappared, having behaving themselves perefectly for months.

Regards
Max P

From my experience with this problem and having had it a number of times, the problems seem to stem from the brakes, and how worn they are or what type they are (only in my case i'm talking here)

Everytime i have renewed my rotors and pads the problem seems to go away and only re-occures once they wear to a certain point.

This time i went to genuine pads and rotors, mainly because the first time i had the lights coming on was after i replaced my first genuine pads and rotors with after market stuff, as they became worn, i started getting the lights coming on, that's my first recollection of my lights coming on.
So hopefully going back to genuine may help, well that's my theroy and i'm sticking too it

Baz.

don't forget play in the wheel bearings,afraid there is more than one cause for this

Thanks Stevo,
I will try what you suggest and clean the reluctor including checking the float on the bearings. I will take the hub off and spray contact cleaner into the sensor gallery upside down. What do you think?
I had to go to a repairer as the fault could only be diagnosed then cleared using Testbook interface. Needless to say they kept the old sensor. I shall also test the impedance of the sensor which I believe is about 1 kohm plus or minus 100 ohm when in good condition.

Hi, Baz, Steveo & Max

I reckon Baz could be on the money on this as my experience has been similar.

2001 D2 Td5.

1.Pads changed last summer and brake squeal set lights on dash off. Coopers changed to genuine pads and pads handled heat better and brake squeal went away.

2. All fine until cold snap hit at Easter and first thing in the morning brake squeal comes back setting lights on dash off again.

3. Car has 138,000 rotors where done at 80,000 and will not need doing again untill 160,000. The pattern with mine is that even though everthing is genuine brake squeal problem comes back after second set of pads are changed and rotors are not. I reckon for some reason problem surfaces when rotors are half worn and second set of pads are put on.

Very annoying.

when my car was still under warranty I had a simialar fault the dealer cleaned the sensor ring it had metal filings in the teeth of the sensor ring,here is some info on the sensors from the wabco site

Speed sensor 441 032 ... 0 and impulse wheel:

Task:

Using a proximity method, the stationary
sensor detects the movement
of an impulse wheel which rotates together
with the vehicle's wheel. Impulse
wheels for light and medium
commercial vehicles have 80 teeth or
fewer.
The output voltage of newer WABCO
sensors has been increased for the
same wheel speed by modifying the
internal design of the sensor. As a result,
ABS operation can still be assured
even given increased air gaps
and even at very slow wheel speeds.
These sensors are identified by an

”S+“

on the sensor head.

Operation:

The bar sensor operates inductively
and mainly consists of a permanent
magnet with a round pole pin and a
coil. The rotation of the impulse
wheel connected to the wheel hub
produces a change in the magnetic
flux picked up by the sensor coil,
thereby generating an alternating
voltage. The frequency of this voltage
is proportional to the wheel
speed.

Design types:

The speed sensor has been especially
developed to cope with the
more exacting requirements of a
commercial vehicle. Good temperature
stability and resistance to vibration
ensure that it operates reliably
even under extreme conditions.

Sensor installation

The speed sensor is mounted using
clamping bush 899 760 510 4 (CuBe)
or 899 759 815 4 (CrNi) and mounting
grease in a hole in the axle stub
or in a special sensor holder. It is
held in a sliding arrangement. On the
front and rear axles, the speed sensor
is pushed into the clamping bush
by hand up to the impulse wheel.
The wobble of the impulse wheel
pushes the speed sensor axially outwards
in the sensor hole after one or
two turns of the hub by hand. It is
moved out to the maximum extent of
the impulse wheel wobble.

Fig. 15 Installation position of the speed
sensor

Note

There is no need to set a minimum
air gap for the sensor since it sets its
position automatically during the first
couple of wheel rotations as a result
of the wheel bearing play and the impulse
wheel wobble.

Technical data

Contact resistance
1150 +100/-50 ohms
Temperature range
-40 °C ... +150 °C

Lubricant

In applications which are exposed to
greater contamination, we recommend
using a clamping bush and
sensor with a thermally stable grease
which is also resistant to splashing
water. This is in order to guard
against corrosion of the hole in the
axle stub and the penetration of dirt.
We recommend: WABCO sensor
grease
1 kg can Order no. 830 502 063 4
8 g tube Order no. 830 502 068 4

Maintenance:

Fig. 16 Installation position of the
components (sectional view)

As well as regularly checking the
wheel bearing play, you should push
the sensor back in

by hand as far as
the stop when working on the wheel
brake.

In order to adjust the speed sensor

(if the air gap is too large) never
use force or an unsuitable tool such
as pointed or sharp objects. Doing so
may otherwise lead to damage to the
sensor cap!

When replacing a speed sensor

we recommend replacing the clamping
bush as well.

Inspection:

Notice the bit about trye size difference .
• The size of all interacting tyres is
allowed to deviate from the nominal
value set in the parameters
by ±8 %.
Individual tyres are allowed to
deviate from the nominal value by
max. ±1.5 %.
• Modifications to the vehicle with
the objective of increasing the
overall speed or acceleration or
modifications to the brake system
may impair the function of the
ADD-ON ABS system.

Amplitude of the sensor signal too low. Check the bearing play and axial runout
of the impulse wheel, press the sensor against the impulse wheel. Check
for a loose contact in the sensor cabling and plugs.

Hi there, I know this might be a bit late but I have had the same prob in my 99 V8 D2 5sp. I had the recurring problem when I first bought the car with Landrover telling me the speed sensor needed replacing. $220 later and the problem was still occurring and of course they won't take the sensor back even though I paid them to tell me what the prob was. I suspected the 75% worn BFs on the car and replaced them with a cheap set of mudders and the brake pads with a lucas set. CAR HAS NEVER SHOWN THE PROBLEM SINCE!!!!
My discs were close to their limit when I had them machined last so these don't ssem to be the prob at all. I suspect that what happens is one tyre circumference deviates out of the acceptable tolerances of the computer and the whole TC / ABS / HDC fails until reset with testbook.

After fitting the new sensor and having the lights come on, I just drove home and changed the tyres the next day when the TC came on again on its' own

BTW I fitted GT Radial 265/80/16s which only just rub on rull lock and perform alright. (they wear very well)

Hope this helps someone as it scared the **** out of me with the cost of some of the parts.