Help finding the ABS Wheel Sensors on W203 needed **Pics**

[Hustler]

Hi guys,

I've got an ABS/ESP/BAS warning light on my car and have had this ever since I bought it 7 months ago. I've decided to have a look at the ABS wheel sensors to check if they're dirty and causing the warning light to come up after reading some threads on this in the past.

I've taken off my front right side wheel and have taken a look but haven't had any luck finding the location of the sensors. I'm not too familiar with this sort of stuff so probably have missed it as this is my first car and the first time i've taken off a car's wheel on my own.

I could see a pair of wires but I couldn't specifically see the exact location where it connects to and it seemed like it goes somehwere into the brake callipers(?) and didn't want to risk taking the calipers off and not being able to fit it correctly and safely back on.

I've taken a few pics and would appreciate it if someone could have a look and help me locate specifically where the ABS sensor is so I can take that bit off and give it a clean if it's dirty.







Some of the pics may need rotating (sorry).

I've opened the front wheel on the driver side. Have I opened the right one? Or am I supposed to be looking at the rear wheels?

Would appreciate any help and advice for a newbie.

Thank you

Car is a 2003 C200 Kompressor Coupe, 1.8L, Manual, Petrol

 

[cleverdicky]

Well there are two fat black wires trailing down the shock. One leads to the brake pad wear sensor (which is on one of the brake pads).
The other wire is the abs sensor

 

[Naraic]

They are on each wheel.

 

[WG M-B]

It's bolted on via the wire that goes into the back of the hub
Not the caliper!

 

[Pathfinder]

Picture 1, left wire. Your problem is more likely to be the exiter ring that the wire aims at and it is incorporated inside the dia of the hub seal.

 

[ourtomtom]

That's OK but what are we looking for in respect of the sensor connecting lead affecting the ABS warning light. If it's not a silly query. Advice on step 2 needed. Daz.

 

[Frontstep]

The reluctor ring, the thing the Sensor aims at gets full of rust and muck with a torch you will see it down the hole when you remove the sensor.
Don't forget the back wheel rings they can snap with corrosion and are available form MB seperately even though they will try and sell you a complete drive shaft.

 

[Pathfinder]

The reluctor ring, the thing the Sensor aims at gets full of rust and muck with a torch you will see it down the hole when you remove the sensor.
Don't forget the back wheel rings they can snap with corrosion and are available form MB seperately even though they will try and sell you a complete drive shaft.

You won't see it on the fronts, it is not visible as it is incorporated within the seal.

 

[Alex Crow]

If it is speculative work based on the ABS light being on, and you have never removed a wheel before, I suggest putting the wheel back on and finding someone who can read out the fault codes for you.

Breaking an ABS sensor while trying to remove it will prove disappointing, especially if it is the brake pedal switch at fault...

 

[Frontstep]

Re reading the lights been on for 7 months !!!

 

[steveE250]

There are quite a few things that can cause those lights to be on. I have been down the same road with my E300 TD. I could not get to the cause without Star diagnosis. Your car might be able to be read with other fault code readers but Star was the only choice for mine. If you can use a multimeter you can however rule a few things out. You can check the sensors for resistance by following the wire until you get to a plug and socket.Disconnect them and check the resistance across the pins. They should if I remember right read around 1Kohm and all be within a few % of each other. You can also check that there is a voltage output by switching the meter to AC mV.
Watch the meter as you turn the hub or disk, you should get a few mV from each sensor. My problem was a broken Reluctor ring on a rear drive shaft. I still got an output but it was not very stuck to the driveshaft and was turning more slowly than the wheel. The diagnosis had the result "off side rear wheel sensor output not plausible.
It could also be the brake light switch even if the brake lights work OK.