ABS Sensor / Anti-Skid Service / AWD issue...
 

Hi all, I'm after some advice (what else?) for an issue on my '05 D5...

The Anti Skid / ABS Service light came on a couple of months ago. Not long after having had all 4 wheel bearings replaced (this may be unrelated).

Took it to my local independent who diagnosed a rear wheel abs sensor fault, which was replaced. Soon after, the fault came up again.

Back to the garage - this time 4 faults I think (reading the Snap-On diagnostic tool over his shoulder): All 4 abs sensors, and the yaw sensor.

He cleared the faults, I drove it round the block, the light came on again, and this time only the front right abs sensor fault came up...

So my question is - do I pay for the front right sensor to be done, or do you think it's more likely to be a fault in the ABS/Anti-Skid control unit - about which I've seen the DIY fix thread somewhere on the forums?

(Also, the AWD isn't working right now, and I think the ABS is also not functioning properly.)

Thanks as always in advance for any advice /experience / hints / tips etc.

I'm in the North East (NE18) if anyone is local and has expertise in exchange for beverages...

It is always best to try and get the fault codes read on a Vida, rather than with a generic scanner, as the codes will be more specific to your problem rather than just a general code.
Given the age of your car, it is quite possible that the problem is the reluctor ring on the front driveshaft; these are pressed onto the outer u/j and have a tendacy to split when rust builds up underneath them. It is a common problem with these cars and, provided the shaft is not stuck in the hub, is an easy and cheap fix.
It is just about possible to check them with the front wheel off and looking into the back of the front hub assembly; when I did mine, it was possible to see where the ring was broken and move it with a screwdriver. New rings are less than £10 from GSF or similar.

Thanks for the advice - I've order a pair from GSF half price too (so less than £10 for both, delivered) and will get them fitted by a local independent. Sounds like about an hour each side?

If nothing is seized, it should be possible to do both sides in less than an hour.

Thanks again - DIY job for someone vaguely competent? Given the bearings and brakes have been done recently I'm hoping things aren't seized up...

If you buy inferior bearings, they are not sometimes compatible with you existing sensors... and will throw errors codes up. Always best to buy Volvo or SKN etc... which are known to be as good as OE.

Thanks again for all the advice.

Spent a few hours yesterday replacing the reluctor rings (abs rings) and the fault seems to have immediately gone away - no more warning lights, no more juddering brake pedal. I’ll check with my local garage this week, and clear any existing fault codes if any are still on the system.

Very simple job - corrosion levels dependent! One side took around 30 mins, the other took a litttle longer... bit pleased to have completed the job, and avoided spending £175 for the garage to (possibly) chase the fault around.

👍🏻😀

Good news.
Any chance of you doing a quick write up?

Any update re awd? This MY is prone to failed spline drive. I hope awd is now OK too?

Ask me how I know...

John l

On the XC90 the front ABS rings are part of the CV and shouldn't be too upset by changing the wheel bearing.

On the rear the tone ring is part of the bearing so could easily be the problem.

Be very clear - cheap bearings = problems.

By Volvo genuine or a bearing brand (i.e. SKF) do not buy the cheap bearings on e-bay (especially from shyster seller BAHUHA) they only last a few thousand miles, if that. I've made that mistake TWICE and never again.

Sensors are only usually a problem if the bearing has failed and the sensor has been damaged by coming in contact with the ring.