Xantia ABS Fault, Intermittant

KP · Unread post by KP » 04 Mar 2008, 10:38

I was wondering if anyone had come across an ABS fault where the light is on when the engine is started and only goes out when the vehicle begins to move at above 20mph or so. Then the light can sometimes come on while driving and then just as it came, go away again. All without warning.

I have noticed that the light seems to come on almost eveyrtime i drop below about 10mph. and then it will almost always go off when speed picks up.

Im thinking that one of the sensors is dying off or one of the rings has been damaged or is covered in dirt but i wouldn't normally think dirt would affect the magnetic pickup of the sensor.

The other option is the sensor itself has been damaged or is misaligned. failing that i guess the ABS ecu is fried

Anyone any pearls of wisdom before i get the multimeter out on the under bonnet connector plugs to find out if they are good or duff?

Strangely only in the last few weeks has it got worse and more occurant...

citronut · Unread post by **citronut** » 04 Mar 2008, 13:46

maybe one of the sensor magnets has picked up some swarf
regards malcolm

Unread post by **CitroJim** » 04 Mar 2008, 18:50

I had precisely this happen ages ago on my 1.9TD. On inspection of a CV joint I found a split boot and grease all over the "Dragons Teeth" of the ABS ring. I gave it and the sensor a good cleanup (after replacing the boot) and no further trouble.

Any sort of dirt seems to upset them although in theory it shouldn't. Flaky rust on the teeth could also be the problem.

Anyways, give the teeth and sensor face a good clean and see how it goes

citronut · Unread post by **citronut** » 04 Mar 2008, 20:26

just dont file the teeth down at all as you will allter the air gap which is a set distance
regards malcolm

KP · Unread post by KP » 04 Mar 2008, 22:08

cheers guys ill check this out at the weekend as just got my wheel bearing done and the door hinge temp welded for £50 +vat which was pretty good i thought

citronut · Unread post by **citronut** » 05 Mar 2008, 19:21

thats not why your ABS is playing up is it!!!!!!!!, sounds to cheap to me
regards malcolm

Unread post by **CitroJim** » 05 Mar 2008, 19:34

That does seem a bit of a coincidence KP. Hope they did not damage the sensor when fitting the new wheel bearing - like I hope they removed it before starting work.

They may not have replaced it quite right and as Malcolm said, the air gap may be wide. Check the sensor is sitting properly in the hub with its mounting flange sitting nicely flush with the hub casting and its securing stud is tight and correctly fitted. It may have worked it's way out a little.

MikeT · Unread post by **MikeT** » 05 Mar 2008, 19:40

Or did they use an arc-welder without disconnecting the sensitive ECU?

KP · Unread post by KP » 06 Mar 2008, 09:29

No the fault has been ongoing since well before the bearing was done guys