ABS Sensor - resistance range

[XantiaExclusiveHDI]

Hi all

Just getting my Xantia ready for its MOT after a couple of years SORN. It will be up for sale soon.

The ABS light was illuminated - and turns out I had an open circuit front right sensor which I just replaced.

However the light is still illuminated. I just measured the resistances at the connector as follows:

FR (new): 1097 ?
FL: 1111 ?
RR:1110 ?
RL: 1108 ?

Which of these would you suspect? Also should the light go out immediately following a out of range sensors replacement - or do you have to drive a certain distance for it to clear?

Thanks!

[VertVega]

According to resistance values, all would be called as "healthy".

Did you drive your Xantia after ABS sensor replacement and the speed was over 20 km/h or equivalent in miles/h?
If the answer is yes then check the condition of the toothed rings starting from front wheels, not broken, no missing parts, not loose ring or etc.

[Mandrake]

Make sure you didn't put the spacer on the wrong side when fitting the new sensor. If you did the gap between the sensor and the reluctor rings would be too great and it won't work. The gap is pretty critical.

Also you may need to drive the car as Vert Vega says before the ECU can tell that you've repaired the fault and will begin to trust the sensor again.

[VertVega]

Correct, the gap is also important.

I remember after the front wheel bearing change my Xantia developed that annoying ABS "feature". While slowing down, for example approaching traffic lights, just before stopping ABS pedal started kicking back.

It took me some days before I found out that the heat shield was connected in a different way than the other wheel's. Heat shield was either under or above the sensor. I can't remember it now After fixing it the problem was solved.

[XantiaExclusiveHDI]

Ahhh - well being the law abiding citizen I am that could prove difficult as it is without an MOT presently due to its being SORN for 2 years...

I'll see if I can build up some speed along my short drive and up the walls - across the roof etc

I did ensure the sensor was mounted first followed by the heat shield then the washer / bolt.

I will have a look at the reluctor ring tomorrow.

Just refurbished the front & rear brakes with Mintex pads / discs & replaced the rear LHM caliper seals. The rear brakes were much easier than I expected having read some of the horror stories on here. The bolts were easy to undo after a night with PlusGas & there wasn't too much in the way of galvanic corrosion between the mating surfaces. The pads had a very slight angle to the wear - and the (factory original) discs had no visible wear groove - I could have re-used them but I had already bought a complete set so I just replaced them. I popped in some polythene gaskets to help minimise any further corrosion issues - I wonder has anyone used Duralac to good effect?

[XantiaExclusiveHDI]

OK - I drove the car up the wall - around the roof a few laps and the ABS light is history!

Thanks guys

[Hell Razor5543]

It only needs to hit 20KMH (a little over 10MPH) for the ABS to be happy the system is working (assuming the sensors ARE working). That caught me out when Gracie had a sensor failure. I replaced it, the light stayed on, and I spent over an hour trying to find what I had done wrong. Finally gave up, had to drive her, went over 20KMH and the light went out.

[XantiaExclusiveHDI]

Yes - had I not been aware that you needed to get the wheels moving to make the ABS CU happy I could have ended up replacing everything

Replaced the LHM today - removing and cleaning the reservoir/ filters in the process. A somewhat cathartic exercise in this weather - will bleed the brakes tomorrow to remove the stale LHM left in the brake lines.

Then she's off for an MOT