328xi front Abs sensor touching axle

Platinum Child · 07-09-2019, 08:36 PM

Getting 4x4 and dsc lights and pulled a code for a front right abs sensor, no signal.

Confirmed with inpa that I am getting a signal, however i pulled the sensor and it has touched the axle. There are rub marks. This is the second sensor that I removed with rub marks. The first time I figured it was just something that got caught it there.

Now I'm thinking that the reluctor ring may have swelled due to corrosion. It looks a little bit rusty, but nothing crazy.

I checked for a bad wheel bearing, but there is no play or indication of a bad bearing.

Does anyone know where I can get just a reluctor ring to replace? Everything I see online is for the rear. Are they the same size?

Not looking to replace the axle, I don't trust FEQ axles and oem is pricey.

Thanks!

gbalthrop · 07-10-2019, 12:37 AM

Some FWD/AWD vehicles have frequent problems with BROKEN "Tone Rings" or Reluctors (toothed-wheel) that the ABS Sensor "reads." That problem is due to rust forming between the drive axle and tone ring causing the ring to expand until it cracks and then spins loose on the axle.

If your Reluctor is still intact (NOT "free-wheeling") then simplest fix is to simply shim the Sensor you have so that it does NOT contact the Reluctor. I don't think the "Air Gap" between the Sensor & Reluctor is that sensitive that it matters if one side of Reluctor is closer to Sensor than opposite side. There MAY be some slight voltage fluctuation, but since the sensor is sending a Square Wave Signal, that should NOT matter.

Please let us know what you find,
George

07-09-2019, 08:36 PM	#1
Platinum Child First Lieutenant 128 Rep 333 Posts Drives: Tiag z4mc Join Date: Feb 2013 Location: new jersey iTrader: (0)	328xi front Abs sensor touching axle Getting 4x4 and dsc lights and pulled a code for a front right abs sensor, no signal. Confirmed with inpa that I am getting a signal, however i pulled the sensor and it has touched the axle. There are rub marks. This is the second sensor that I removed with rub marks. The first time I figured it was just something that got caught it there. Now I'm thinking that the reluctor ring may have swelled due to corrosion. It looks a little bit rusty, but nothing crazy. I checked for a bad wheel bearing, but there is no play or indication of a bad bearing. Does anyone know where I can get just a reluctor ring to replace? Everything I see online is for the rear. Are they the same size? Not looking to replace the axle, I don't trust FEQ axles and oem is pricey. Thanks! __________________ IG - @sd262
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07-10-2019, 12:37 AM	#2
gbalthrop Brigadier General 2697 Rep 4,031 Posts Drives: 2007 328xi E91 Join Date: May 2017 Location: Fairfax Co, VA iTrader: (0)	Some FWD/AWD vehicles have frequent problems with BROKEN "Tone Rings" or Reluctors (toothed-wheel) that the ABS Sensor "reads." That problem is due to rust forming between the drive axle and tone ring causing the ring to expand until it cracks and then spins loose on the axle. If your Reluctor is still intact (NOT "free-wheeling") then simplest fix is to simply shim the Sensor you have so that it does NOT contact the Reluctor. I don't think the "Air Gap" between the Sensor & Reluctor is that sensitive that it matters if one side of Reluctor is closer to Sensor than opposite side. There MAY be some slight voltage fluctuation, but since the sensor is sending a Square Wave Signal, that should NOT matter. Please let us know what you find, George
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