Xantia ABS

This is the Forum for all your Citroen Technical Questions, Problems or Advice.

Moderator: RichardW

Post Reply
higgy
Posts: 36
Joined: 21 Apr 2002, 03:19
Location: United Kingdom
My Cars:

Xantia ABS

Post by higgy »

I have a problem with the ABS on my Xantia TD. The ABS light is on constantly. I had a diagnotic check done which showed a faulty front sensor. I replaced the sensor (although this was some months later)and the light has not gone out. Is there any procedure to reset the ECU? I have had another diagnostic check but the results were "could not communicate with ECU". I have checked out the link on this forum for the BX ABS problems but the connector numbers made no sense at all when compared to my car. I know the ECU is a common problem on these cars,does anyone know what causes the ECU to fail or what fails inside the ECU. Also will the brake system still function with the ECU removed.( Im thinking of opening it up to have a poke around inside)
Any ABS experts out there?
DaveQ
Posts: 1
Joined: 18 Jul 2002, 21:36
Location: United Kingdom
My Cars:

Post by DaveQ »

Had exactly the same fault as you've just described on my 94 Xantia td.
If the abs light stays on when you start it then it is not a wheel sensor problem. If you take it to a citroen dealer to read the fault off their computer and they tell you there has been no fault stored then it is definitely an ABS ECU (or brain) fault.
This seems to be a very common fault, so being an electronics engineer i decided to take it apart to see if i could fix it myself.My abs light flickered on & off for a while before it permanently stayed on so i thought it would be something simple like a dry soler joint but they seemed to be ok. Besides that when you look inside, all the ic's and components are covered in some type of lacker, presumably to stop water damage so it makes it very hard to resolder, and without proper diagnostic equipment it would be very hard to fault find on it.
You can remove the abs brain & drive as normal with proper working brakes (without ABS of course).
There are a few people in the UK who will swap or repair these but they will not touch them if they have been opened so you have been warned and will cost around £190. A lot cheaper than Citroens quoted £600 for a new one.
Your best trying a breakers yard for one. I managed to get one for £85.
Trevor C B
Posts: 18
Joined: 09 Mar 2002, 04:40
Location: United Kingdom
My Cars:

Post by Trevor C B »

When my ABS light stayed on I had a mooch around the web for a new black box. There are companies who will test and exchange but some will not accept units which have been opened !
I found the following links - I did not use the Companies as my problem was a sensor fault. I cannot report on how good they may be
http://www.carelect.demon.co.uk/index.html
http://www.bba-reman.com/abs.htm
http://www.woollard.com.btinternet.co.u ... ad.htm#ABS
Remeber that running you car without the ABS working will mean a MOT fail.
Trevor C B
Posts: 18
Joined: 09 Mar 2002, 04:40
Location: United Kingdom
My Cars:

Post by Trevor C B »

When my ABS light stayed on I had a mooch around the web for a new black box. There are companies who will test and exchange but some will not accept units which have been opened !
I found the following links - I did not use the Companies as my problem was a sensor fault. I cannot report on how good they may be
http://www.carelect.demon.co.uk/index.html
http://www.bba-reman.com/abs.htm
http://www.woollard.com.btinternet.co.u ... ad.htm#ABS
Remeber that running you car without the ABS working will mean a MOT fail.
alan s
RIP 2010
Posts: 2542
Joined: 26 Jan 2001, 15:53
Location: Australia
My Cars:
x 6

Post by alan s »

Not wishing to rock the boat unnecessarily, but the ABS on my BX was constantly on and it turned out to be an internal break in a wire from a sensor caused by a bracket attached to the strut having broken off (prior to my purchase) and thereby allowing the sensor wire to bounce & flex around. It was fixed as a temporary measure by reinforcing it and repairing the bracket.
When I was having the problems with it I made several enquiries in an attempt to isolate the problem & amongst the things to try were removing & cleaning the sensors as well as earth points associated with them as well as thoroughly cleaning the serrated wheel that the sensor works on. After doing this, the ABS light would come on, go off as the car started and then come back on again when the car rose on its suspension.
It could be that the ECU for the ABS is caput but the point I would make is that I would be trying the other avenues first as very few companies will give a money back guarantee based on a wrong diagnosis and they are a pretty expensive item.
It should also be remembered that the sensors are basically fairly powerful magnets which have a natural desire to pick up piles of metal filings from rotors etc which do affect their performance and which I have heard previously will do a much better job if kept clean.
Hope things aren't quite as serious as first thought.
Alan S
pwatson
Posts: 263
Joined: 22 Apr 2001, 03:02
Location: E Midlands
My Cars:

Post by pwatson »

Dear all,
I know nothing about ABS except that when the light stayed on on my Xantia I took the car to my local independent bloke and said "I hope it's not the ECU" He replied that it was extremely unlikely since in 10 years of testing ABS systems on Cits he had only had to replace 2- they are very reliable". He put his computer thing on it and it was a sensor - front as usual. I suspect that the "common problem" of ECUs is not as common as we are told and that Alan's advice is very sound - check everything before splashing out a fortune on a new ECU - it probably is wiring or sensors. Hope so.
PhilW
Phil
Post Reply