Xantia ABS light intermitent

mark21td · Post by **mark21td** » 17 May 2010, 14:22

I have an intermitent fault with my ABS, the light stays on sometimes,
Sometimes it goes out while driveing but sometimes it stays on for a few days, other times it doesn't come on for weeks.
It goes through it's normal diagnoses, goes out and then comes back on.
It's been checked out on a Lexia by DickyG (thanks agine mate) and showed no faults at the time.

The car is due it's MOT soon so I need to get it sorted quick.

Any ideas.

Post by **CitroJim** » 17 May 2010, 14:32

Mark, I'd be very tempted to suspect a sensor is borderline.

Get an accurate (ish) ohm meter on to them and check their DC resistances. If one looks a bit high compared to the others, that's the one that may be giving the fault.

Also, give your dragon's teeth a good clean. Muck and dirt on these and on the pole faces of the sensors themselves can give problems.

mark21td · Post by **mark21td** » 17 May 2010, 14:35

Thanks jim, I'll have a look tomorow.

mark21td · Post by **mark21td** » 18 May 2010, 21:41

Ok I've checked the resistance on all the sensors
FR = 1.092
FL = 1.102
RR = 1.094
RL = 1.103
So they all seem quite closely matched,
but what a sod of a job that was, who decided to put the conectors there

I cleaned up the frunt sensors and the drivesharts have been replaced in the larst couple of years so the teeth are nice and clean.

I couldn't get the rear sensors out as there stuck fast, but I did clean up the teeth as they were quite rusty.

Not had chance for a test drive yet so I'll see how it goes tomorrow.

Xaccers · Post by **Xaccers** » 18 May 2010, 22:17

You didn't test them by disconnecting each one did you?
Not that there's anything wrong with that, but it's a PITA.
You can just disconnect the ABS ECU connetor and test there.
There are pin diagrams for both S1 and S2 Xantias in other ABS threads.

mark21td · Post by **mark21td** » 18 May 2010, 22:31

Xac wrote:You didn't test them by disconnecting each one did you?
Not that there's anything wrong with that, but it's a PITA.
You can just disconnect the ABS ECU connetor and test there.
There are pin diagrams for both S1 and S2 Xantias in other ABS threads.

Yes I did it the hard way, while spraping up my arms I was thinking there must be an easier way to do this, I know I should have done some reading first

DickieG · Post by **DickieG** » 19 May 2010, 05:59

Mark, give me a shout if you want me to carry out a diagnostic test for you.

mark21td · Post by **mark21td** » 19 May 2010, 10:19

DickieG wrote:Mark, give me a shout if you want me to carry out a diagnostic test for you.

Yes please Richard, as the light was still coming on this morning, but went out after a 35 mile drive, I just can't work it out.

citroenxm · Post by **citroenxm** » 19 May 2010, 12:46

have you actually tried a Safe Emgergency stop to see if the ABS works at all?? Light on or off??

I had a Xantia S1 estate, light out, but still Skidded!!

Also had that on a Hatch.. Were as on my XM, light on and ABS still works!!

Paul

mark21td · Post by **mark21td** » 19 May 2010, 14:29

I know it works when the light is out, but I've never checked it with the light on.

Is it an MOT fauil if the light is on ?

citroenxm · Post by **citroenxm** » 19 May 2010, 15:07

Absolutly! Weither the system works or not - light on instant fail...

Paul

Old-Guy · Post by **Old-Guy** » 19 May 2010, 19:50

Had exactly the same fault on both of our Xantias - 'faulty' O/S/F sensor. Cost my daughter a mint to have her's diagnosed and a new sensor fitted. Fault reappeared after a couple of months. Permanent cure for both cars was to unplug at the ECU and clean-up the connectors - I also checked and cleaned the individual connector for the 'faulty' sensor on our Xantia. Strangely, the fault re-appeared for a few minutes a few weeks ago, but I may have confused the ECU by briefly spinning one front wheel on loose gravel when pulling away in a hurry.

mark21td · Post by **mark21td** » 23 May 2010, 15:20

DickyG has just plugged my Xant in and found the F/N/S sensor is at fault.
Thanks again Richard.

Just had a look on ebay and found this

http://cgi.ebay.co.uk/Brand-New-Citroen ... 255875c4d4

Anyone used these people before ?
Are they any good ?

MJM · Post by **MJM** » 24 May 2010, 12:56

Yes, same sensor fns. It arrived in a couple of days. It looked o/e quality. (You can tell by the standard of the plastic mouldings) It was a perfect fit and worked with no problem.

mark21td · Post by **mark21td** » 24 May 2010, 14:08

Thanks MJM, I'll order one now.