ABS comming on too early

[dandrei]

Hi guys !

I have a problem with my car when breaking. When breaking gently and reaching low speeds (like 20 km/h and lower towards 0 km/h) I feel the ABS is comming on, I feel the pedal vibrating. I find this behaviour abnormal. I mentiond the fact that the onboard ABS yellow led never comes on and all 4 ABS speed sensor are newly changed (I thought a senzor was faulty, but it's not). I went with my car at a BMW dealer and had this issue diagnosed. They said that all electronics are ok (ABS control unit, sensors....) and the issue could be the wheel bearing on the rear left because the ABS sensor is reading its values from the wheel bearing.

I have hesitated to change the bearing because I'm not convinced the abs speed sensor is reading values from wheel bearing so this is why I'm asking you. The scope is to fix the brakes, not the bearing unless it's necessary.
Do you have any ideea where the speed sensor is taking its value ?
And also, do you have any other ideea regarding this behaviour of the ABS system ?

[assmoothasfcuk]

hi,

was this issue ever fixed, or has someone had something similar? the issue i have is the same, although its on my e36, just trying to get to the bottom of it.

any help would be appreciated.

many thanks,

Danny

[andes]

Originally Posted by dandrei

Hi guys !

I have a problem with my car when breaking. When breaking gently and reaching low speeds (like 20 km/h and lower towards 0 km/h) I feel the ABS is comming on, I feel the pedal vibrating. I find this behaviour abnormal. I mentiond the fact that the onboard ABS yellow led never comes on and all 4 ABS speed sensor are newly changed (I thought a senzor was faulty, but it's not). I went with my car at a BMW dealer and had this issue diagnosed. They said that all electronics are ok (ABS control unit, sensors....) and the issue could be the wheel bearing on the rear left because the ABS sensor is reading its values from the wheel bearing.

I have hesitated to change the bearing because I'm not convinced the abs speed sensor is reading values from wheel bearing so this is why I'm asking you. The scope is to fix the brakes, not the bearing unless it's necessary.
Do you have any ideea where the speed sensor is taking its value ?
And also, do you have any other ideea regarding this behaviour of the ABS system ?

Hi,
I had trouble with ABS on my 523i 2000. I took it to an independent garage, who said two of the sensors needed changing. I gave the go-ahead and the problem was similar to what you report. Turned out that they had used non-BMW parts and the problem was finally fixed when I bought two sensors from the dealer and replaced them myself. I would advise you check if the sensors are from BMW. (The parts I bought had a BMW marking).

The 5 series sensors pick up signals from the 'reluctor ring', a series of 'teeth' on the outside of the bearing. I would check the sensors before changing bearings.

[Nick_318is]

You can pull the fuse and try to outbreak the system, just be careful in turns.

[darkhorse737]

pedal vibrating as in a chatter like vibration is not ABS or sensor problem.... it is a warped rotor problem... have your rotors turned and brake pads replaced.

ABS feels different... ABS coming on is a constant resistance on the brake pedal and not a vibrating one .

[harrison doug]

i was getting the same thing. i found my abs exciter rings very dirty and corroded..i wire brushed them when i was replacing brake rotors(front) after cleaning exciters that premature abs activation went away..i have an '87 535is

[Bimmer M.D.]

You mean braking? Anyway, replace the abs rings.