ABS fault

stevenlizuk · Post by **stevenlizuk** » 16 May 2006, 01:25

Hi All,

Can anyone tell me of a simple test to detect if and ABS sensor has died on the car.

The warning light on the dash came on yesterday and is on full time.
I am assuming a dodgy sensor but don't know how to check them.

Naturally, being a Xantia owner I own a multi-meter, will it help me this time?

Cheers Steve

alan s · Post by **alan s** » 16 May 2006, 01:32

The simplest basic check is to put the meter over the sensors and whichever one is different; there's your culprit.
Only problem is that often the cause is an internal break and in these cases as soon as you move it to do a test, it often shows up as being OK.
The nearside front is the most common one to fail for some reason or other.

Alan S

stevenlizuk · Post by **stevenlizuk** » 16 May 2006, 22:47

Thanks Alan,

That sensor was replaced a couple of years back.
Could be the sensor that takes the worst of the weather being at the kerbside?
Thanks
Steve

Gammy leg · Post by **Gammy leg** » 17 May 2006, 10:52

Steven,

You want to set your multimeter to read resistance ( ohms ) for this test. As Alan said they all want to give around the same reading.
You can also carry out a voltage check but the wheels need to be spinning to do this.
Also worth checking the reluctor rings on each hub for missing teeth or foreign bodies and the gaps between the sensors and the rings.
If all these check out OK then you should start looking at the ABS ECU and associated relays ( thats when the fun really starts )

HTH

Gammy

jeremy · Post by **jeremy** » 17 May 2006, 18:24

The ABS is constantly monitored by its computer which communicates the results to you via the warning light. As your light is never going out it must be a fault that shows when the system is static. I think the static test is simply a continuity test of the sensors - so faults with the toothed wheels, gaps between the sensors and the toothed wheels etc are not in issue.

Meter the sensors - the chances are the culprit will show as an open circuit - so will be obvious - but record the resistances which should all be very similar.

citronut · Post by **citronut** » 18 May 2006, 22:59

usualy its the cable at fault where it is constantly flexed,on the fronts every time the steering is turned,on the rears every time the suspention arm moves,the wires become fractured in side the outer sheath
regards malcolm

stevenlizuk · Post by **stevenlizuk** » 19 May 2006, 00:03

Thanks all for the help,

The light ha ssince gone out soI 'm going to have to wait for it to fail again to look for the problem.
I have a friend who works in a garage with access to diagnostic gubbins, but his wont work on cits or pugs as they change their software every year or so. Typical.

Chhers again,

Steve