Hi

My XJS 4.0L ABS light just turned on the mechanic told me to run it for a while because it could be humidity in the sensors.

I did run it but it persists. What's the best way to diagnose. Will a relay be in question? Or may I have to replace the ABS sensor, if so is it the ABS sensor or does it have another name?

Thank you for helping

Sergio

 

Sergio,

There could be a whole number of reasons why the light is one, from a spurious sensor signal (if you're lucky) to a failed ABS valve block. I've never heard of "humidity in the sensors" as a problem. There are a huge number of posts on here relating to the ABS system and illumination of the warning light.

It's a very complex braking system and is well worth reading up the section in the workshop manual before trying to address the issue.

Start by trying to clear the fault code through a battery disconnect. When you start the car, note the two brake lights and if they extinguish. Does the ABS pump cut in, build up pressure and cut out? If the ABS light is now out, drive down the road and see if it cuts in. If it cuts in, was it when you were braking or not?

I'm sure, with careful diagnosis, you'll get to the bottom of it.

Good luck

Paul

 

Hi Sergio,

The ABS Can be a bit of a 'nightmare' so my first question is going to be, do the Brakes work as normal?

This may not be apparent under 'Gentle Progressive Braking' so find yourself an empty road and driving at a Safe Low Speed, Jab the Pedal hard and fast, like you may find yourself doing in an emergency Stop.

Does She pull up in a nice straight line, as if the ABS isn't working as it should, you could find your Car is diving to the left or right.

Which can be so 'Violently' that you could find your Steering Wheel, is snatched out of your hand.

So taking care and being aware that can happen, give that a try and then let us know the result.

 

As I understand, ABS, barely, if at all, it modulates pressures.
In theory, four locked wheel skid can not happen.
The system will release just enough to allow braking at it's max, "just short of locked"!


And, in theory, one should feel a slight pulsation in the pedal under hard braking. I think the ABS in my 94 Jeep works, but, I've never felt the pulsation


I do understand the Jeep ABS architecture is altogether different than the one Jaguar sourced.


Being an old school guy, I prefer non ABS braking.


Carl

 

Hi Carl

The Teves ABS System which you find on the XJS can result in causing some unexpected problems if it fails.

Which could be because of a blockage in the pin ***** hole of a valve, or if one of the very brittle wires inside the valve block breaks.

And in the event that should happen, then the chances are that the Car will dive to the right or left, in situations needing a sudden application of the brakes.

This in fact has happened to me in two different XJS's and when it does the ABS will do its best to throw you off the road, which is every bit as scary as you can imagine.

So I'm with you in saying, that I much prefer a Car, that has normal braking rather than one that has ABS.

 

Hi Sergio

There is a possibility that it could be a Fuse so check that first.

Which may be Corroded, or Faulty in some way.

The Fuse is under the 'Knee Pad' on the Passenger Side, under a drop down panel, that you can undo with a coin.

There are lots of Fuses in there but the (Two) that do the Brakes are are just grouped together on their own.

One will say 'Pump' while the other will say 'ABS'

DO NOT REMOVE THE PUMP FUSE OR YOU WILL LOSE ALL THE BRAKES!

But have a look at the other one that says ABS and then give it a Clean or replace it with a New one.

A faulty fuse can result in the ABS light coming on, which may be intermittent if the Fuse is loose or Faulty.

So nothing to lose by giving that a try (its worked before!)

 

Humidity in the sensors? That's a new one.

Do you have a trip computer? There's got to be a way to pull the ABS code on your car. Do,you have an OBD port under the drivers dash? I know a 94 was before its time, but I figure you might be close enough.

If no OBD, I wonder what is the way to pull the code?

 

Yes, a 95 4.0 litre has got an OBD port. And of course the Service manual, which we all know you must own if you're going to run an XJS, describes the 32 electrical integrity diagnostic tests that can be undertaken.

Paul

 

You're going to want to take it to a shop that can read the ABS codes then. Should cost you about $150. You may even have to take it to a dealer. In any case, make sure you call the shop and ask before you take the car over.

It could simply be a dirty sensor. The code will tell you which sensor it is, and you can try cleaning it first. If that doesn't help, a replacement will be likely.

I'd get the code pulled. I bought a device from eBay that can read it for $150. So far I've broken even. It does reorient oxygen sensors and reset the TPS as well.

 

Thank you very much everyone. Awesome response from all! Really nice.

The Jaguar does indeed veer to the right at breaking! As "orangeblossom" says, could it be the right sensor?

As "Vee" says I will give it a try to replace the 'ABS' fuse.

Thank you for all the help, I will post the results.

Sergio
By the way I am in Switzerland and here any repair costs an Oil Rig in Dubai. :icon_lo lsign:

 

Sergio,

If the car is really diving to the right under hard braking, it's not the sensor. That's not what OB was saying. He was referring to a failed valve in the main ABS block. A failed sensor will only disable the ABS, it won't make the car veer. It's worth checking the fuse as that's easy, but I doubt that's the problem.

If you've done as I suggested, reset the battery etc and you've still got the light, run through the 32 diagnostic tests in the Service Manual (or get a mechanic to do it). And if you or the mechanic hasn't got the proper manual, don't let him go near your brakes!

Good luck

Paul

 

Hi Sergio

Don't get too excited, it isn't looking good!

The chances are that you have a blocked Valve or if not a broken Wire in the form of a Ribbon Connector, inside the ABS Valve Block.

And just to Cheer you up even more, New Valve Blocks are unavailable.

Blocked ABS Valves can be caused by not changing the Brake Fluid on a regular basis but more often than not, by replacing the Brake Pads.

When you change the Brake Pads on an XJS unlike many 'Normal Cars' its absolutely essential, to undo the 'Bleed Screw' and Clamp off the Brake Pipe.

As if you force the Pistons in the Callipers back, in order to get the New Pads in

Then you can send Brake Fluid (which will almost certainly contain some microscopic particles of 'Crud') Back up to the Valve Block, which can then reek havoc with the ABS

Which will then almost certainly mean, that you will have to do your best to rebuild it, or maybe try and get one from a Scrap Yard.

Even if you rebuild it there is no guarantee of Success, although you will have a much better chance if one of the very Brittle Ribbon Wires has broken.

Which are so incredibly Fragile, that you'll have to rewire the whole thing and make sure that you are a 'Soldering Ace' or even more bad things can happen, (where do I send the Flowers) Lol

As for the Valves, they would need to be cleaned in one of those Special Ultrasonic Cleaners that they use for cleaning Jewellery so you must be tripping over those, in your neck of the Woods or should that be Mountains.

Try all the other fixes first and lets hope its as simple, as a faulty fuse.

Or else read on:

https://www.jaguarforums.com/forum/x...photos-140828/

 

Hi Sergio,


I spent 6 months tracking down the fault that caused my ALBS light to be permanently on in my '96, 3.6. I will not bore you with the details as I suspect my fault was car specific. The key thing is you have to be methodical and logical.


As people have said, the full Jag manual is superb in terms of fault finding and as a very minimum you need to refer to this. There are 32 tests that you can perform with the aid of a multimeter that will inform you as to what is not working. Also there is a means of getting the ALBS light to flash a code to advise you of what the fault is - again this is described in the manual and you don't need special equipment to read it.


Good luck,
LeeP

 

ABS light was solved a week ago. ABS Jaguar Original Front Right Sensor DAC11150
Ordered from:
Nick Milligan
Harper Porsche Jaguar
Parts Manager
865-934-2822

 

Sergio,

Glad you got the light sorted. I would suggest that you really need to get the veering under braking sorted. That sounds worrying and it won't have been cured by a replacement of a faulty sensor which disabled the ABS.

Good luck

Paul