[eljay]

Yes, from the pictures of axles I see for my car, the front xdrive axles have the rings, but rear axles do not.

[wrongmark]

Just to add my bit to this, I had the same problem a few years ago. I bought two new reluctor rings off of ebay with some specific glue included. The drive shafts were pretty easy to remove, i cut off the old reluctor rings, sanded/filed away the rust and glued the new ones on. Cleaned up the sensors and refitted, they've been fine since. I believe garages will generally replace the whole drive shaft for this as I think the cost of the drive shaft is cheaper than the labour. Mine is a 2011 E90 320i.

[Blue Angel]

Originally Posted by Silver Streek

As I understand it the 6 cylinder engined cars don't have the reluctor ring set up, that set up is used on 4 cylinder cars.

Please correct me if I am wrong.

My Wife's car is a Canadian model 2011 323i, the base model below the 328i, comes with a 2.5L six instead of a 3.0L. Rear sensors are the reluctor ring type. Car was built in the USA late 2011.

I put a new sensor in to replace the one that was worn from the swollen reluctor ring, but I left it out about 1/16". Took it for a drive, all lights cleared within 30 seconds. I'll be adding a washer under the M6 sensor bolt as others have done, and on both sides in anticipation of the other side not being far behind having the same issue.

[jwilalex]

Washer trick only works for so long, I got just over 2 years using them but eventually the rings pass the point of no return. The rust lifted parts end up way too close and rainy weather makes it more susceptible to error or the none worn/raised parts end up too far away with the washer in. Ultimately replacing the rings cures all, I actually bit the bullet and had them done a couple of months back while I was getting both rear shocks changed.

[N8N]

Originally Posted by AndyVR

Thanks for the advice. The problem has got worse with the DSC light flashing every journey, at any speed, with power loss and braking, and sometimes all three yellow ABS/brake/DSC lights on.

Still no error codes. I figured out how to view in the live data wheel speeds in INPA, went for a slow drive, and yes I got one wheel (Rear left) jumping up from 30kph to 60kph randomly!

Have you found that the issue was just the abs wheel sensor, or any issues with the pickup in the wheel bearing?

Did you fit genuine or aftermarket sensors? I've heard of issues with cheap sensors, amazed that they are available for around £15 upwards - in my VAG days I was used to paying £50-70 for an OE quality sensor from ECP/GSF. ECP seem to list the same parts for early E90's as late ones, so no confidence buying from there. GSF only list rears for 2007-2009.

I got a price for a genuine rear wheel sensor from Hereford BMW for £88 delivered, wondering if I should just go with that?

I would replace the sensor. I have already replaced two on my car because of degraded wire insulation.

The TPMS thing seems to be a different problem however, AFAIK no E9x uses inferred TPMS from WSSs they all have sensors in the tires

[jwilalex]

No TPM sensors in my 2009 E90 tyres/wheels… tyre pressure is calculated via rotational time duration with a flat being seen as minutely different to a properly inflated one. I think it also needs around a 10% difference to even consider a tyre as being lower than the rest (probably more)

[Blue Angel]

Washers installed on both sides, everything ok right now.

Our '11 E90 has no TPMS, works on wheel speed.

[N8N]

Originally Posted by jwilalex

No TPM sensors in my 2009 E90 tyres/wheels… tyre pressure is calculated via rotational time duration with a flat being seen as minutely different to a properly inflated one. I think it also needs around a 10% difference to even consider a tyre as being lower than the rest (probably more)

wow, really? My '09 uses proper sensors. I wonder which cars didn't get them?

[AndyVR]

Originally Posted by jwilalex

Washer trick only works for so long, I got just over 2 years using them but eventually the rings pass the point of no return. The rust lifted parts end up way too close and rainy weather makes it more susceptible to error or the none worn/raised parts end up too far away with the washer in. Ultimately replacing the rings cures all, I actually bit the bullet and had them done a couple of months back while I was getting both rear shocks changed.

Just came here to ask that very question!

The rear sensor I replaced (and spaced out with a 1.5mm washer) in 2017 has started throwing dash lights and error codes again (permanent dash lights now)

Hmmmm so I might be looking at new driveshafts/rings then, if the rings get that distorted - due to Ill health I can only do small jobs now, changing driveshafts would be out of the question for me, and also trying a new sensor with different spacing washers over and over would not be good for me either.

Might have to go to a garage then

[AndyVR]

I recently removed the rear sensor, In 6 years it had worn away again (so the abs ring is getting bigger due to the corrosion underneath it) but the ring itself looked in good nick, and was pretty round still, worked out I needed a 3mm thick washer to give about 1mm clearance, and fitted a new Febi sensor from ecp. I used two 1.5mm large nylon washers that I happened to have (screwfix, for seating taps).
Cleared the codes and tested on a long road trip, all working perfect again.

I'm not saying it would work on every car, e.g. if the rings are distorted/badly egg shaped you would get bad readings then errors.