1st Gen R53 Cooper S Most liked posts in thread: Wheel Speed Sensors (aka Pulse Generators)

Ok ABS module swapped out and that took care of the 5DF5 internal fault code.

I still did get weird intermittent LF wheel speed sensor issues. It seemed to like throwing a code on a hard left turn, swapped that out as well with a VDO unit and all is finally well, or at least there are no codes at the moment.

Next weekend's track adventure will be the real test.

 

Fair question.
The code says it is bad, but when I took it out to inspect it was barely dirty. It came out really easy too, after a quick clean with a dry paper towel it looked pretty much like new, but still threw a code.
Dirty


And then cleaned


Not really much difference.

Is there a way to electrically test these things? What are they supposed to do when the wheel is spinning?

 

Oh and BTW, when I take the blue connector apart on mine it looks like it is brand new in there. It is definitely hermetically sealed, how could yours have possibly been dirty???

 

Thanks for the lead Paul, I will keep that in mind. BTW, when remedied, these codes will clear themselves after a few ignition cycles right? I am hoping they are not any of those hard codes.

 

You know, I might be 'chasing a ghost' here.
This all started with the ABS module spazzing out on the track in late June in a heat related failure. I have confirmed I am getting the 5DF5 (ABS Control Internal Failure) code, and have been since late June.

When not on the track at max temp, typically all is well, no dash lights and fully functioning everything.

Very recently I started to get this wheel speed sensor code, and so now I am going after that first as it is an easy fix.

Thinking about this a little more....It is certainly possible that my bad ABS module is continuing to degrade and the root of the Wheel Speed Sensor code.

I think I will focus on that damn ABS module first and get that remedied, and then see what I get on the wheel sensors.

 

All ABS faults/codes that are actively showing the dash lights result in a dead ABS system. You will still have normal braking function, just no ABS at all.

With good tires on dry pavement and normal street driving this is not an issue and you have some time to remedy.

For my specific case the wheel speed sensor issue was intermittent so when the dash lights were on I knew ABS was off. I was getting what is referred to as the trifecta dash lights, this seems to be the classic tell of a wheel speed sensor problem and actual codes provide the additional detail of which wheel.

To answer your question directly.... No, additional braking was not being applied and I do not think that is possible. ABS faults result in no ABS, not more ABS being activated randomly or over aggressively.

 

Most if not all vehicles do it the same way with a Hall effect transducer as the sensor picking up a magnetism change from a toothed reluctor wheel mounted on the shaft/axle/etc.
This wheel will have one spot with a missing tooth or a larger gap between teeth thus allowing the transducer to 'see' a change.

These days a reluctor wheel failure is very rare.

And yeah, as Paul mentioned earlier 99% of the time on our cars a simple removal and clean is all that is required to fix.