BCM-0042 Wheel sensor right rear. Mechanical fault
 

Happy New year chaps.

2008 XC90 2.4 SE Manual.

Im 'front' loading this thread - the car is going to the mechanic on Monday. I don't think its a huge issue.

I've had the yellow ABS/Anti Skid service warning triangle and a 2nd dash warning message of Brake Assist service required for a week or more now.

DTC shows, BCM-0042 Wheel sensor right rear. Mechanical fault.

Cleared it, washed the sensor areas on all 4 wheels, still appears.

I have reluctor rings which I bought for the front... BUT, are the the same size for the rears ?

Anyone else had any experience of this code ?

Cheers

From VADIS:

On the front wheels, the pulse wheel is pressed onto the outer constant velocity joint and the wheel sensors are located radially in the shaft housing relative to the pulse wheel. On the rear wheels, the pulse wheel is pressed onto the hub and the wheel sensors are located axially relative to the pulse wheel. The rear pulse wheels can be replaced. Both the front and rear pulse wheels have 48 teeth. In the event of a fault in any of the wheel sensors the following systems will be disengaged or will not engage.

I don't know if they are the same size.

This eBay ad seems to show that the rear rings look very different from the front.

https://www.ebay.co.uk/p/Magnetic-AB....c100009.m1982

Excellent that Greg.... Thanks very much. Ill get one of them in... just in case.

All the best.

And then you get this.....

https://www.ukpartsdirect.com/abs-pr...ring-1013.html


Ill take the wheel off tomorrow and have a gander at which I have

Any conclusion to this?

Yes - the front uses reluctor rings (castelated) - older tech.

The rear uses tone rings (smooth) as used on Ford derived platforms (V50, P3 V70 etc.)

The tone rings * I think * are a sleeve on the end of the bearing, not the CV joint as on the front.

Check the wheel bearing - I've seen these errors before being caused by play in a bearing rather than a failure of the tone ring.

You may be able to do it without taking the bearing out but it will be a fiddly, swearing a lot job - personally I would just pull the bearing.

If you buy a new bearing get a genuine one or branded from a bearing maker like SKF. Do not buy cheap on e-bay especially the £40 from BAHUHA as they don't last 10% of the life of good ones. My advice from several bad experiences and mistakes that I will not personal repeat :-(

Thanks Guys. It only happens when the car turns left.... and the DTC indicating to the right wheel, it may well be bearing play. Ill check it before I do a fiddly replacement.

Ive got castellated rings and a tone ring.... just to cold to fit as yet. Ill report back.

Deffo wheel bearing play if on when turning....

The magnetic ring on the right rear bearing was incredibly scored, by the sensor itself. Whilst theres no noise or play in the bearing whilst its without a wheel on, there is no way the bearing isn't knackered given the marks on the ring...

New bearing on order.

Thanks for all your helps chaps.... as usual.