ABS sensor w211

[ayvo]

If the rear sensors are the same you could try swapping rear sensors side to side? If the intermittent fault moves then its the sensor. If it doesn't then its local to the hub/brake in question. I wonder if there's any excessive end float/wear on the rear hub bearing causing lateral movement? Does the fault sometimes occur on cornering rather than travelling in a straight line?

considering the sensor has been changed twice now, isnt it quite likely that the sensor is fine? and it comes on at random times, not when cornering. sometimes when the car isnt even moving..

 

[ayvo]

Agree with Grober's thinking, if the fault is intermittent then one possible cause is variation in the gap between the reluctance ring and the sensor head. The gap is critical to detecting rotation so any float can change the gap, also check the seating of the sensor it must be fully home in it's mounting, any crud that stops it sitting fully home will increase the gap and could make intermittent miss reads more likely.

is there any way the gap can be measured to make sure its right?

 

[Deleted member 149005]

considering the sensor has been changed twice now, isnt it quite likely that the sensor is fine? and it comes on at random times, not when cornering. sometimes when the car isnt even moving..

Or the fault is in another sensor and the error code is pointing you in the wrong direction...happened to me when I had a faulty sensor hence both on same axle replaced..

 

[ayvo]

Or the fault is in another sensor and the error code is pointing you in the wrong direction...happened to me when I had a faulty sensor hence both on same axle replaced..

ive ordered another 2 speed sensors, just have to wait for them to arrive. 1 for front left and 1 for back right, as rear left and front right have already been changed. ill change them myself and im hoping this fixes the issue. thanks

 

[pmcgsmurf]

Battery/alternator good, when was battery last changed?

 

[Deleted member 149005]

Don’t the sensors require coding to the car?

 

[pmcgsmurf]

Don’t the sensors require coding to the car?

No, just an impulse ring.

 

[ayvo]

Battery/alternator good, when was battery last changed?

changed the battery about 2 weeks ago, but the abs problem was still there even with the old battery, and with this one too. I think the alternator is fine

 

[ayvo]

Don’t the sensors require coding to the car?

I don't think they do no

 

[pmcgsmurf]

changed the battery about 2 weeks ago, but the abs problem was still there even with the old battery, and with this one too. I think the alternator is fine

Both batteries (car may have only 1 depending on year)?

 

[ayvo]

Both batteries (car may have only 1 depending on year)?

the one under the cabin air filter under the bonnet was replaced like 2 months back, the main one under the trunk floor was replaced about 2 weeks ago

 

[pmcgsmurf]

the one under the cabin air filter under the bonnet was replaced like 2 months back, the main one under the trunk floor was replaced about 2 weeks ago

Should rule out the batteries so back to the sensors, wiring or control unit.

Wouldn't be the first time I've had a cheap scanner get Left and Right mixed up, or even a mechanic.

 

[ayvo]

Should rule out the batteries so back to the sensors, wiring or control unit.

Wouldn't be the first time I've had a cheap scanner get Left and Right mixed up, or even a mechanic.

im not sure about it mixing it up but the sensor has been checked, as well as all the wiring going from the sensor all the way into the control unit so I'm guessing all that's fine. guessing it could just be a case of them getting mixed up and it means the right then?

 

[ayvo]

either that or something related to the gap as stated earlier within the post obviously

 

[Mattns]

I'm not familiar with the position of the sensor and reluctance ring on this particular car but on the ones I've changed measuring the gap would be almost impossible due to access. However as someone previously said check for play in the wheel bearing and if the sensor is fully home in it's mounting the interplay of both could cause intermittency.

 

[ayvo]

okay so I'm wanting to change the front left sensor myself, I just wanted to ask is it harder or easier than the rear one and is it a similar procedure as I've changed the rear one before but never a front one.. also I was told the bumper has to come off can someone confirm if this is true or not? thanks

 

[ayvo]

okay so the speed sensors have been changed, and the abs light is still coming on anyone else got any idea what it could be?

 

[ayvo]

I've even had the esp module replaced now, but the abs light is still intermittent. can anyone help, what else could it be?

 

[mersum1es]

what does error code says?

 

[ayvo]

what does error code says?

rear left speed sensor still..