ABS sensor w211

[hog]

rear left speed sensor still..

Have you replaced the reluctor ring on drive shaft had same problem so did this ok now
Hog

 

[ayvo]

Have you replaced the reluctor ring on drive shaft had same problem so did this ok now
Hog

Yeah, reluctor rings have been changed..

 

[ManofKent]

My W211 has exactly the same issues. Abs/esp light on, no cruise control, then it may not happen for days.
The codes say right hand rear sensor problem.

What I do notice is if the light comes on while driving, the auto box sort of jolts and sits in a lower gear for about 1/4 mile before settling down again.

So a question, is there a relationship between the auto box and the abs speed sensors, and could this be a clue to the op 's issue?

 

[Gatley]

I would suspect a wiring or connector issue, we are talking low level signals here, if things are not perfect a fault will flag. is there any correlation with wet weather? get someone competent to check LOADED ground and signal wires from control unit right back to the sensor connector. A simple multimeter test may not show up an intermittent bad ground or signal connection. Are they analogue or Hall effect sensors? 2 or 3 wire? If I were doing it I would scope the sensor at the control unit itself, in real time. They can be fickle things.... Other things rely on reliable ABS sensor signals, hence gearbox glitches et cetera.

 

[ayvo]

this is an old post but got the problem diagnosed and sorted.. for anyone wondering, it turned out to be one of the pins in the sbc pump connector being loose and having a loose connection, hence it being intermittent and rough roads making the abs light come on.. I stated earlier in this post that all wiring and connections had been checked but all that was checked by another mechanic who somehow didn't figure that out and said all was fine, so I apologise for that..