Now-ABS

XANTIA_ML · Post by **XANTIA_ML** » 29 Aug 2006, 13:25

Hi!
I have 2 situations (unexpectable):
1. 2-3 sec after driving beginning ABS lamp-ON. Great braking performance-no ABS.
2. ABS lamp-off, ABS works, but braking is not proper-the ABS "releases" brakes too early. Further pressing on the pedal solves the problem, but anyway-it is not normal braking.
What is the problem?
Thanks ahead.
Mark

Mandrake · Post by **Mandrake** » 29 Aug 2006, 20:54

Most likely faulty wiring to one of the ABS sensor, or the sensor itself is faulty.

If the ABS light goes out after starting the engine the sensors test ok for a simple ohms test that the computer performs, but if the light comes back on a few seconds after driving it means either one sensor is not providing any pulses, or one of the cables is going open/shorted with suspension movement.

Have a search for ABS using the forum search as there is lots of recent discussion on how to diagnose this...

Regards,
Simon

XANTIA_ML · Post by **XANTIA_ML** » 30 Aug 2006, 06:11

Thanks, Simon!

After some topics rewiewing I understand, that when ABS light is ON-the system is out of service.
The problem is that sometimes it becames OFF-so the system return to work with poor braking performance.
I intend to remove ABS's fuse (No 6?) and this way to put the system OFF with foreseeable behavior until I"ll care it.
Is it OK or diletant's fantasy?

Thanks again.
Mark

Mandrake · Post by **Mandrake** » 30 Aug 2006, 07:07

Hi Mark,

Yes, you can safely remove the fuse for the ABS computer and it will return the braking function to the same behaviour as any Xantia without ABS installed. (EG braking will work normally but you will be able to lock the wheels with hard braking....)

However because the ABS fault light will now be permanently lit (while driving) it won't pass an MOT test, so you'll need to at least get the problem sorted out before the next test.

Did you manage to find the message thread which gave the pinouts of the ABS computer plug ? It would be worth doing an ohm meter check of each of the 4 sensors AT the plug where it goes into the computer, perhaps while someone bounces the suspension and see if there is an obvious fault - good sensors measure 1050 ohms +/- 100 ohms.

Regards,
Simon

XANTIA_ML · Post by **XANTIA_ML** » 30 Aug 2006, 11:46

Hi, Simon!
Thanks a lot for exhaustive explanations!

Unfortunatelly i have not enough skills as car electrician (my experience reach up to fuses only

) to perform this job safely and on professional level.
So-I"ll go to CIT-service next week

.
Best regards
Mark

h2ocooler · Post by **h2ocooler** » 30 Aug 2006, 14:46

Well you can always pull the bulb for the MOT. if its not showing a fault they cannot fail it on ABS.

citronut · Post by **citronut** » 30 Aug 2006, 17:07

no you cant just remove the bulb as that will fail through it not lighting at all,as the test for ABS is the light has to come on and then go of after so many seconds,so if the tester is doing his job corectly he would fail it with no light showing at all
regards malocolm

XANTIA_ML · Post by **XANTIA_ML** » 31 Aug 2006, 14:06

Mandrake wrote: However because the ABS fault light will now be permanently lit (while driving) it won't pass an MOT test, so you'll need to at least get the problem sorted out before the next test.

Hi, Simon!

Has an MOT test any relvance to rest systems in the car?
Is it important for history or ABS functioning after fixing of the problem?
I am almost sure that I go too far, but when speaking about computer you may suppose any options.

Regards
Mark

Post by **philhoward** » 31 Aug 2006, 18:47

I'm guessing, Mark, that you're not in the UK, hence references to the MoT test may not apply - the annual test applied to cars over here. On an UK MoT test, the fuction of the ABS (if fitted) is tested by the response of the ABS lamp - in fact as long as the lamp comes on and goes off after "x" seconds, its a pass, even if it goes into fault mode the first time you hit 30mph!

From a safety and operation of the car point of view, then removing the fuse/bulb will not affect the braking system of the car; its just that you won't have ABS anymore.

XANTIA_ML · Post by **XANTIA_ML** » 01 Sep 2006, 09:53

So, for testers in UK my Xantia is OK-the ABS lamp goes off in 1-1.5 sec.

Here in Israel-I don't remember that testers checked ABS as You describe. But they do check that the lamp will be off and breaks efficiency-on the stands.
Since my annual test will be in april-I hope to fix the problem before.