Thoughts On This ABS Fault?

[sledlife]

Hi, I've had a fault recently which is the ABS and Run Flat indicator inoperative one, which I understand is often down to a faulty ABS sensor. I've taken my car to the local garage and they said they can't get a specific fault reading, just the following that has been thrown up. They said they can't get any further info as they haven't got the tool to get into the ABS hub or something to look into it further?

Would the following indicate a faulty ABS sensor, or possibly something more? Thanks

 

[Smiley]

It looks like it is the front right ABS sensor that is the problem - but could be the sensor itself, wiring or could even be the reluctor ring or dirt/rust around the ring or the sensor or the surface that the sensor mounts to. Needs a thorough visual inspection before deciding to buy a new ABS sensor.

 

[slade1]

Had this problem with CLK, new wheel sensor fitted 65£ for then part and 50£ labour.
Simple job for Indie with MB STAR diagnostic equipment

 

[OneForTheRoad]

Delete and see which codes return , that seems a bit to in-depth a report tbh. For a simple abs sensor . Normally you'd get codes for that.

 

[markjay]

The brake vacuum sensor is at the front of the servo, it's just a matter of unplugging it and replacing it, though you'll need to have thin and long fingers to get to it...

And, if your W204 is the face-lift model, then the green light on the ECO button will be off, because the brake vacuum sensor is a prerequisite for the Start/Stop system.

You may also have a faulty wheel speed sensor, I don't know, but if so, then my recommendation would be to also replace the speed sensor on the other side, on the premise that if one went, then the other will follow soon....

 

[markjay]

No 70:

 

[sledlife]

The brake vacuum sensor is at the front of the servo, it's just a matter of unplugging it and replacing it, though you'll need to have thin and long fingers to get to it...

And, if your W204 is the face-lift model, then the green light on the ECO button will be off, because the brake vacuum sensor is a prerequisite for the Start/Stop system.

You may also have a faulty wheel speed sensor, I don't know, but if so, then my recommendation would be to also replace the speed sensor on the other side, on the premise that if one went, then the other will follow soon....

Thanks for the replies everyone, great support on here as always.

@markjay your post was interesting as my car is both the face lift and the green eco button hasn't come on for some time, which makes me wonder whether it is the brake vacuum sensor.

I'll pop to the Merc garage near me this week and get a price for one as it sounds like it might be worth trying to replace it, and then look at the wheel speed sensor later if needed, thanks

 

[geoffus]

Get yourself a ICarsoft MBV2 if you can, it will help you with loads of diagnostics.
If it is a speed sensor it will even show you each wheel speed when you are driving for proper analysis.
Has lots of great features for the average Mercedes owner.

iCarsoft MB V2.0 - Mercedes, Sprinter & Smart Professional Diagnostic Tool

Supplied with a two year warranty, you’re guaranteed to get great results with the ICarsoft MB V2.0. This diagnostic tool is developed to diagnose a variety of car issues.

ljmcardiagnostics.co.uk

 

[BlackC55]

Brake vacuum sensor and a wheel speed sensor are your issues.

 

[sledlife]

Brake vacuum sensor and a wheel speed sensor are your issues.

Thanks, I'm going to try and pick up or order the two tomorrow

 

[BlackC55]

Get them from your local MB dealer. They are not expensive and they will probably stock them.

 

[sledlife]

@markjay @BlackC55

Just to update this thread, I replaced the brake vacuum sensor and a wheel speed sensor and it's resolved the issues. No more ABS fault and now (unfortunately?) my start/stop light is back on.

Both jobs weren't too bad. The bolt that holds the wheel sensor on is a bit fiddly but that's about it. I found the brake vacuum sensor quite tough to get off. I could just about reach it and spin it but it wouldn't budge out of the hole! In the end I had to just grab it on one end and pull it at an angle. Genuinely thought I was going to snap it off in the hole, but you get to a point where you hear the air escaping and you know it's close to coming out then. New one goes in much easier. Cost £135 for both part from dealers.

Thanks for the help everyone!