abs cpu

greggpask · Post by **greggpask** » 05 Oct 2003, 17:30

Hi,
what a great forum for citroen owners out there. I wonder if someone can help me with the problem with the abs cpu,which i believe is acommon fault in Citroen Xantia's. I have the 1.9sx td, and the abs warning light is contantly on? The cpu in question is for a 1994 on L reg,which according to forums is the one that goes wrong. The question is, have Citroen recognised this and has there been any redress that owners can make?

AndersDK · Post by **AndersDK** » 05 Oct 2003, 17:41

I don't think it's the ABS ECU (cpu) that's your problem.
On cars with several y's in service - it's allways a wheelsensor or it's cabling that's chuffed. You may even have a couple of dodgy sensors - it's very common - due to the harsh environment out there in the wheel arches.

Post by **RichardW** » 06 Oct 2003, 15:26

It could well be a problem with a wheel sensor - you need to do all the checks for that first. However, problems with this ECU are far from unknown - my mate had to put a 'new' one in his 93 TD. He dismantled the old one and found it did not have a proper ciruit board, just a flexible layer stuck onto the inside of the ecu cover. IIRC he got the error codes read for about £30.
Richard

first-things-first · Post by **first-things-first** » 06 Oct 2003, 22:59

Hi Greggpask
I used to have a Xantia 1.9TD SX (93 'L'). That had done 96K when I got it and when I sold it had done 150K. In the intervening 4 1/2 years I replaced every ABS sensor. Almost like clockwork an ABS sensor would go every year. Different one each year. The ABS computer was changed when I got the car (saved me £600 !). Easy enough to fit a sensor yourself but about £80 ish each.
As per RichardW, I would get the fault codes read it probably is a sensor. It should tell which sensor is faulty. I wish they would be like Rovers. You short a conection and it flashes to indicate the sensor at fault or whatever. Much better.
Regards
Andrew

pwatson · Post by **pwatson** » 08 Oct 2003, 04:18

We had a Xantia L reg and an ABS light on. Went to our local independent dreading that the ECU had gone. The chap said he had been servicing Xantias for 8 years, had heard stories about the ECU being unreliable but had yet to replace one - it was always a sensor that had gone. With that he put his computer thing on it, diagnosed a faulty front nearside sensor and replaced it (about £70 inc VAT, labour etc? I think - my wife paid!!)
There is a good article here (David Woollard's site)
http://www.woollard.com.btinternet.co.u ... ad.htm#ABS
about testing ABS. It's written for the BX but I think it also applies to Xantias

alan s · Post by **alan s** » 08 Oct 2003, 05:46

I can't speak for the Xantia but with the BX the sensors are as simple as disconnecting an aerial lead (similar type of connection.)
They have 2 under the bonnet & two under the rear seat. With a multi meter just do a reading on all of them & whichever one is the "odd man out" that's your problem child.
In most cases it's usually only an internal break in the lead going to the sensor & can sometimes be fixed if the point of the break can be located.
Alan S

Homer · Post by **Homer** » 08 Oct 2003, 07:53

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by pwatson</i>

The chap said he had been servicing Xantias for 8 years, had heard stories about the ECU being unreliable but had yet to replace one
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
I'll add my name to the list of ECU failures. An M reg petrol (1994 I think) with the early type (expensive) ECU. (added) This was a few years ago, the car was only about 3 years old at the time. Took it to a Citroen dealer to have the codes read. They ordered the part but it didn't turn up after 3 days so I told them not to bother and got a 2nd hand ECU at less than half price.
But considering the age of the cars with those ECUs I would expect most of the faulty ones have been replaced by now and most faults will be due to deteriorating sensors/wiring.

alan s · Post by **alan s** » 08 Oct 2003, 10:14

From what I've heard & read over the years, the "ECU factor" should really apply in new or near new vehicles mainly due to the main faults in them (excluding physical damage) being due to dry joints, imperfect circuit boards causing tracking or internal components with a manufacturing fault in them and showing up within the first couple of years.
After that, it's usually a case of being contaminated by water or having s severe knock or the most common, someone getting a power spike through it. I usually look at the ECU as being the last resort because in all honesty, complicated & involved they may be, but there's nothing in there to wear out so providing they're looked after, they should last almost indefinitely.
Alan S