Abs Sensors

[john f]

Wi64 ML 3OO CDI 2010

What is it with these Abs sensors
I have has three fail in the last 18 months all different wheels
the only one not yet gone is the rear r/h side
What happens is that the ABS light flashes and the brakes lock on !!
Diagnosed with my Icarsoft tool which tells you which wheel is at fault , Superb tool for about £80.00
Changed the Left Front this weekend And cleared codes all ok at the moment
When the latest one failed the brakes would try to lock occasionally and It wouldn't change gear even with the paddles
I have bought some spare sensors just in case
Its quite disappointing with a car of this Marque
I have a 27 Year old Porsche 911 with the original ABS sensors

John F

 

[Submariner1]

Wi64 ML 3OO CDI 2010

What is it with these Abs sensors
I have has three fail in the last 18 months all different wheels
the only one not yet gone is the rear r/h side
What happens is that the ABS light flashes and the brakes lock on !!
Diagnosed with my Icarsoft tool which tells you which wheel is at fault , Superb tool for about £80.00
Changed the Left Front this weekend And cleared codes all ok at the moment
When the latest one failed the brakes would try to lock occasionally and It wouldn't change gear even with the paddles
I have bought some spare sensors just in case
Its quite disappointing with a car of this Marque
I have a 27 Year old Porsche 911 with the original ABS sensors

John F

Good question. 28 years MB ownership, 10 new MBs .. never even heard of an ABS Wheel Speed sensor let alone a reluctor ring untill this year!

This year do a search and one is swamped with folks with an ABS ESP problem? That in many cases is the WSS ir the reluctor ring.

Sadly I got stung £££s for 4 from a main dealer (long story). The issue was linked to low voltage and a suspect earth on the EPS Controller, so masked the MBII diagnosis of first the FL, and then only the other 3 sensors. So I and the Mobilo tech felt it unlikely all four had gone at once... must be the earth!

I really trust the top tech at the maindealer, and he showed me readings proving all three had gone south, and the fouth was very marginal (note the fourth had also has throw a fault code 5 times in the past month).

He basically said its very common to see 2 go at the same time, and extremely common to see the other one or two blow out within a few months. Add MBs policy of always changing both on the same axles and you are pretty much looking at changing all 4! (Except if one spuriously goes early).
He just said they take a real hammering, road salt and extreme heat. Possibly the first owner let the brake pads get very low, which can create more heat than a slightly fuller pad?


He also explained on my car, the ABS - ESP controller compares the reading from the WSS to its known service specification, but also compares it to the other wss on the same axle, (and as I have EPB and adaptive brakes, kt also compares a new front sensor to the rears ) that might explain your lock up and MBs Policy.
(Note it may be possible to get a second-hand working sensor, and insert it into your system and it will be be fine, i.e. has the same level of degradation).

OK I get all that, but what I cant understand is how do they all (all three) go at once!

Hey after all its only a connector, a meter of wire, and an earth ring, and a plastic tube with I guess an inductive coil in it?. Its not a complex Amplifier, incorporating a MOST AGW etc. :-/

My best guess is these Councils have added something to the road salt, that maybe corrodes those rings the securing bolt goes through, and possibly something corrosive leaches through the (degraded by heat) plastic tube.

Oh well just extremely pleased to have no fault codes or warning signals.
And it also seems to have solved my low voltage.

Left for two days would normally deliver 12.2V to 12.4V .... hey presto checked yesterday 12.7V
They suspected having a faulty rear wss stoped the EPB and or ESP shutting down so quickly, and apparently the car wakes up periodically and checks things like the Parking brake!

 

[john f]

Most informative
As mentioned I have also changed 3 sensors all Non genuine so now I have one original on the
Rear
My Idea was to replace the final one for the sake of it but I notice that its different branding to the other three
Huco from Eurocarparts
What was interesting or more realistically annoying was that the front sensor was in short supply with a week lead time
Perhaps a high demand wiped out the stock

Do I put on this other new sensor ??

John F

 

[mattkh]

Wi64 ML 3OO CDI 2010

I have a 27 Year old Porsche 911 with the original ABS sensors

John F

But the Porsche is a weekend car and there is no rust/dust on the reluctor rings.

 

[Submariner1]

Most informative
As mentioned I have also changed 3 sensors all Non genuine so now I have one original on the
Rear
My Idea was to replace the final one for the sake of it but I notice that its different branding to the other three
Huco from Eurocarparts
What was interesting or more realistically annoying was that the front sensor was in short supply with a week lead time
Perhaps a high demand wiped out the stock

Do I put on this other new sensor ??

John F

If it works, no dash message and no fault codes. I personally would leave it till it breaks.

 

[john f]

That's what I will do then
The rear one could be changed on the roadside if I get another lock up away from home
I will keep my star shaped socket and wrench , flat screwdiriver in the boot and diagnostic tool in the glove box

Thanks for the reply

John F

 

[pomm001]

I'm having similar issue with my low mileage C350
Replaced the OSF sensor with a TRW one... looked identical but the car didn't like it, spin the wheel and no output, swapped it over to the other side ( which was good) still no reading.
Replaced this with a genuine one and all OK..... or so i thought 3 days later its comes on and off again
Waiting to get a decent scan tool to check live data to clear codes and start again
Anyone had similar issues ?

 

[RUBBER_UNDIES]

Have you looked at the abs ring? Are your brake disc shields rattling?

 

[pomm001]

I'm having similar issue with my low mileage C350
Replaced the OSF sensor with a TRW one... looked identical but the car didn't like it, spin the wheel and no output, swapped it over to the other side ( which was good) still no reading.
Replaced this with a genuine one and all OK..... or so i thought 3 days later its comes on and off again
Waiting to get a decent scan tool to check live data to clear codes and start again
Anyone had similar issues ?

The ABS ESR Tyre pressure lights constantly on now
Have got myself an I carsoft MB2 tool and checked the live data from the wheel sensors and now the opposite side is not recording a speed,so guess its another 75 or so quid but i have a feeling in my water its not over yet.
A run through the live data pulled up 'Drehratensensor' ? flashing up occasionally fault 53336/6058 for a split second then fluctuates between-0.22 0.31
Anyone have any ideas ?
Strange thing is scanner does not show any stored fault codes ?
Help

 

[Dennis Camp]

Did you resolve this. I had exactly the same problem, no codes.