Is this an ABS fault?
 

Hi all.
Been a while since I've been on here. Had no problems with car and, well, just keep forgetting to pop in !

Until today.
A few weeks ago I noticed that, on turning left, at slow speed, if I brake I get a grinding type noise from front N/S (I think).
It's not pads / disc, I've checked them. The car has been MOT'd since this started and no problem with brakes flagged up (other than parking brake is barely working, but that's a job for another time!).
It feels like the ABS is coming on for that wheel alone, is this possible?

My gut instinct is sensor or reluctor ring. Does this sound right? I have to re-install VIDA on my work laptop, so haven't managed to read codes yet. Is there anything else I could look at in the meantime?

I seriously doubt it is ABS kicking it, you would have to be braking hard for that to happen.
ABS does not work at slow speeds anyway.

Jack up the car, ideally with both front wheels off the ground.
turn the wheel by hand at full steering lock and see if you can feel / hear anything

Thanks.
It was only MOT'd two weeks ago and nothing flagged up. I did have a look over it while it was in the air (friendly MOT guy).
It's so intermittent that I can't reproduce it on demand to start working out the cause.
If it isn't likely to be ABS, then I have two faults as I had an ABS warning yesterday. :angry_smile:

Just re-installing VIDA at the moment to start checking the error codes. Unfortunately, in trying to get my cheap code reader (bought for the V70) to read the codes, I reset them, so the ABS warning has cleared. Hopefully it will be stored in the CPU.....

I thought you meant the noise was the ABS activating.

It could be something else, but you need to inspect

Well, got VIDA back up and running and have a list if issues
Hey, ho! Most are minor.
However, it has confirmed my gut instinct that whatever is happening under braking, I do have an issue with front N/S ABS.
It's either sensor or ring, but won't diagnose further without taking things apart.

Can the ring be seen without taking driveshaft out? I presume not.
Might just buy a new sensor and ring so that I only have to do the job once..

I took a photo of the graph produced in Vida of the wheel speed on both front wheels ( I presume this data is measured by ABS rings).
Blue is N/S. The intermittent drop outs are, I think, the cause of the issue.

I decided to bite the bullet today and have a look. I removed the sensor and, with the aid of an inspection camera, checked the ring. I found that it has indeed split.
So I've doused the strut bolts with Plus Gas and slackened, then refitted them. Checked the drive shaft will knock out and ordered a new ring.
So that's next weekend's job ready.

Excellent diagnosis.
Shows how invaluable that VIDA can be and how powerful graphed results are.

Shows also that not every issue is an electronic issue: your's is purely a mechanical issue.

Here's hoping.
To be honest, if the ring doesn't fix it, the sensor is easy to do...