[Frankb_8]

So I finally fixed my passenger side real wheel bearing. I Went to a local shop and the guy did it for $100 and I bought the F.A.G. bearing myself from a local shop. The car feels amazing now and no nasty noise or shake anymore. However, I am getting the ABS/Brake lights on now (annoying). The mechanic checked everything again and said that he was not sure why they were popping up since everything was connected/put on right. I came across a post that states the only fix for this is to put the OEM bearing on? Any help is greatly appreciated. Thanks !

[Rickygst]

Check for codes. Maybe a damaged sensor and this is assuming everything else is correct

[Frankb_8]

No codes, Mechanic checked sensor and it seemed okay.

[Abax335]

Bearing could have been installed backwards (magnetic ring facing the wrong direction or the wheel on the axle got damaged or knocked off that is read. Don't remember exactly which the e90 uses

[Efthreeoh]

If the ABS light is on there has to be a trouble code in the DSC module. You didn't say if the mechanic is a BMW-trained mechanic and what code reader he used. If he didn't use a BMW scan tool then he'll not see a trouble code. If he used a BMW scan tool but did not select the option that some tools ask for, if the car has DSC, then the scan tool will not scan the DSC module and not find the code.

I've not yet broke down the rear hub on the E90 to replace the bearing, but I have replaced the right rear wheel speed sensor because my car has an issue with damaging the sensor. I do not think the rear wheel bearing has an effect on the operation of the speed sensor. An earlier post suggested that the bearing was installed backwards and the "magnetic ring" is not correctly positioned. I think the bearing can probably be installed backwards, but again I don't think it would have an effect on operation of the speed sensor. The "magnetic ring" is really just a pulse modulator wheel that interacts with the sensor. The Hall-effect (wheel speed) sensor is where the magnet is, not in the bearing. The pulse modulator wheel is built into the rear wheel hub drive flange. You can see the pulse modulator wheel when you remove the wheel speed sensor. It generates a modulating pulse for the sensor to pick up. The pulse modulating wheel is just square blocks (valleys) cast into the face of the hub drive flange.

On my car, I lost the right rear speed sensor in August 2015 and replaced it then. In late December after only 5,600 miles, I lost the right rear speed sensor again. I found that the replacement sensor from August was rubbing on the face of the pulse modulator wheel and eventually wore through the plastic casing and damaged the speed sensor magnet. Last weekend I replaced the speed sensor and upon reassembly discovered the new sensor again rubbing the pulse modulator wheel (i.e. the hub flange). So I used a small washer to back the face of the sensor away from the hub drive flange. BMW changed the part number of the wheel speed sensor in April 2014, so I think the new part is a tad bit too long.

I suggest that you ask your mechanic to replace the speed sensor. Look at the old one when it comes out and see if the face of it has been in contact with the hub flange. When he installs the new sensor, have him hand-spin the hub a few times and remove the sensor to check that the new sensor is not, or is, contacting the hub flange. If it is hitting the drive flange it will have light scratches on the plastic face of the sensor. The fix is putting a small thick washer (about 1MM thick) on the mounting bolt between the sensor body and hub. This brings the sensor face away from the hub drive flange. Just for shits and grins, I also fit an o-ring (I had laying around in my parts bin) over the body of the sensor just to help seal the sensor against the hub.

Hope this helps.

[dbjb]

Originally Posted by Frankb_8

So I finally fixed my passenger side real wheel bearing. I Went to a local shop and the guy did it for $100 and I bought the F.A.G. bearing myself from a local shop. The car feels amazing now and no nasty noise or shake anymore. However, I am getting the ABS/Brake lights on now (annoying). The mechanic checked everything again and said that he was not sure why they were popping up since everything was connected/put on right. I came across a post that states the only fix for this is to put the OEM bearing on? Any help is greatly appreciated. Thanks !

Frank B,
Did you ever figure this out? I just ran into the same problem with my rear left sensor. I'm thinking we can troubleshoot/problem solve together.

Let me know, PM or respond.

Thanks!