W203 C240 ESP/ABS/BAS Problem!

[skymastor]

Hi Guys,

I've had a check through the forums and cannot seem to pull up anything relating to an issue I now have with my C240. So, I thought I would throw it to the floor for comments and suggestions before I start to shell out more money!

Well, it all started 2 weekends ago when I fitted new front wheel bearings to my yr 2k W203 C240. I replaced all bearings, races and rubber seals. All went in fine without any hassle. When I came to drive the car, a funny noise came from somewhere which I could not identify (which I thought was the gearbox), the car would not go above 10kmph as it landed in limp mode! I was then stuck with a car making a funny unidentified noise, 10kph speed in limp mode and ABS/ESP/BAS faults flashing all over the place in the dash! I re-checked the work and all was in order. I was totally stumped!

In the end I was left with no other choice but to take it to a stealer. The guys there checked it out and found that the rubber seals in the bearing kits were the wrong type because they did not have a magnetic strip in them for the wheel sensors and this placed the car into limp mode because no motion was sensed in the front wheels. They replaced the seals and the car drives again.

However, after they had replaced the seals, they also found that the front two wheel sensors needed changing too. They did this and the faults with the ABS/ESP/BAS still persisted. The DAS system then told them that the ESP box on the ABS pump that housed the ESP, BAS and ABS control modules needed replacement too because the DAS/STAR told them! MB Part number for this that they gave is A203 545 17 32, with the original on my car being A203 545 16 32. The price for this was 950 euro!!! As it is now, the car runs, but when the brake is applied that funny noise that I could not identify actually comes from the ABS pump that holds the control unit that MB says replacement. The noise is the same noise that is made as if the ABS system is in normal operation if you brake on a loose surface and the ABS takes over! Then after 50kph, the ABS warning light comes on, ESP/BAS/ABS faults are shown in the display, the systems are then turned off, allowing me to drive without problem, but without ESP/BAS and ABS!!

After a 500 euro bill for what they had done, I took my car with all the remaining faults in the hope to buy this unit from a scrapers so that I could cure my problems. I bought a unit with the exact same part number as my original one fitted to the car (A203 545 16 32) and also from a newer build year, but low and behold, the same problems are there with the same funny noise and the ESP/BAS/ABS turing off after 50kmph!

I ran carsoft on my car and it tells me that the the problem with the Traction/ESP is only that the front right hand sensor (which is actually the front left as you sit in the car because carsoft locations are given from the front of the car looking at it!) is open circuit and the resistance is wrong and needs checking. Bearing in mind that both front left and right have been replaced! I run live data on the ABS/ESP and I get signals from the sensors which relate to the speed that I drive at and from this I assume that the sensors are giving the correct readings to the control unit and works fine if live data says so? I'm confused! However, I cannot get a response from the ABS and BAS units when I run carsoft though!

So fella's, the story is, after putting a new ESP control unit on (second hand thou) as recommended by MB, I still have the same problems with the noise from the ABS pump and the ABS/ESP/BAS turning off after 50kph, so I would assume that the ESP control units are OK? Right? Also, I get no response from the ABS and BAS modules in carsoft so I dont know if this is normal or they are blown? Or if that are actually contained in the ESP control unit?

Does anyone have any ideas on what the problem is please? Any info is appreciated..

Oh, so you all know, I have run this through the suppliers of the parts and I am waiting if they will take responsibility on what happened to these electronic parts after fitting the wrong supplied wheel bearing seals.

Thanks in advance...

 

[BlackC55]

I will have a think about this one.

its a bit tricky....

 

[Diesel Benz]

While experts are thinking, can you clarify did you change the ESP control unit only, not the whole ESP unit with the hydraulic part and specifically the electric motor? Motors wear out, mainly brushes, could the noise be from the motor.

The yaw rate and lateral acceleration sensor is calibrated to the ESP control unit. Now if you swapped unit but are using the old yaw sensor, your ESP cannot be working right (I would not expect fault codes though).

 

[skymastor]

I did exchange the ESP unit only, however, I did get the ABS block which it was attached to with the one from the scrappy but did not change this because MB said it was only the control unit and the block was fine. I did ask them and followed their advice. I will at the weekend change the block too.

Still does not explain why carsoft only says that one of the front sensors is open circuit but live data shows a speed pulse from all four and I get no response from the ABS and BAS modules!! Strange...

Thanks for the advice so far fellas.. Speak soon....

 

[lynall]

So its pointing to the control unit again, if you have a signal from all 4 yet the box cant see it, its got to be duff, be strange to have 2 duff ones though.

Seems even stranger that it was fine before wrong seals fitted. are you sure they havent damaged one of the sensors when fitting it?

What voltages are each sensor producing? when the wheel is spun at a steady speed.



Lynall

 

[skymastor]

I don't know what voltage the sensors are producing, but I do know that MB changed the fronts and replaced them with new ones. All through DAS/STAR... I know... Bizarre...

 

[BlackC55]

I am sure there is another control unit for the esp.

 

[skymastor]

I would think so too, because the unit I replaced (A203 545 17 32) just says ESP on it, and I also get ABS, BAS as well as ESP faults showing in the display.

Does anyone actually know and can Identify where the ABS, BAS and ESP units are situated on my W203?

Thanks guys....

 

[BlackC55]

Whats the first six numbers of your chassis?

 

[skymastor]

WDB2030612F

Cheers...

 

[skymastor]

Any other thoughts fella's

 

[Diesel Benz]

Any other thoughts fella's

Did you sync your steering wheel angle sensor?

 

[skymastor]

If you mean full lock from side to side then yes I did..

 

[BlackC55]

Give me a call tomorrow on 02392 570123 and I will have a look through Wis and try and guide you on the right path of what to do next.

 

[skymastor]

Hi BlackC55..

Thanks for your advice and help. I will call you tomorrow.

Kindest regards...

 

[skymastor]

Hi BlackC55,

Tried calling you there and got your answer machine. I will try again later or if not, Monday.

Regards.

 

[skymastor]

Hi BlackC55,

Thanks for the advice earlier with the pinouts for the front sensors. Well, I have just tested the wires from the sensor plugs to the main connector on the ESP control module and as thought, the continuity is fine.

After this I ran carsoft diag on the ESP module and it still had stored "C1101 Right front wheel speed sensor open-circuit, loose contact, plausibility" I cleared this and the ESP module came back free of errors and reported ok. Normally after this when I run the car, the error returns. However, this time after running the car, the ESP, ABS and BAS faults still apeared in the display and after 30mph, the ABS light came on leaving the ESP, ABS and BAS systems turned off. Running diag on the ESP module again, the right front wheel sensor error did not return!! Success!! But still the ABS light came on again after 30mph with ESP, ABS and BAS faults still flashing away in the display!! Strange!! Finally, I also ran the vehicle showing the live data for the ESP system, which gave speed readings for all four wheel sensors! WTF!! Unbelieveable!

So, to conclude,

1. live data shows speed readings from all four wheels!
2. EPS module now shows clear of the right front wheel sensor fault!
3. ABS/ESP/BAS faults still show in the display and all these systems turn off after 30mph with the ABS light on!
4. Taking the front wheel sensor plugs from their sockets and re-fitting them possibly made the right front wheel sensor fault clear and go from the ESP module?

So fellas.. Any thoughts?

On a separate note. I also too have a SRS light fault that carsoft reports as "B1037 Ignition circuit Front right sidebag Open Circuit" As a test, I uncoupled the plug under the drivers seat for the seat belt lock switch and when I ran carsoft diag again, apart from the original fault above, it also reported "B1055 Front left seat belt lock switch has short circuit" Now, how can the right hand drivers seat belt lock switch be reported as the left hand seatbelt lock switch? Another strange thing! Would I be right in saying again that carsoft's left and rights are the wrong way round because they use left and right as looking stood in front of the car and not sat in it? Any thoughts or experiences shared on this will be greatly appreciated too.

Incidental, if the front right sidebag is the other way round and is located in the left front passenger door and the circuit to this is open, I have also noticed tonight too that the MB sill light in the passenger front door does not illuminate now, but the drivers front right still does! Could it be possible that there is a power supply fault which exists to the drivers door that causes the sidebag open circuit error and the MB sill light not to illuminate? Just for reference, the electric window, curtesy light in the door and door switch all powerup and work fine! Another strange one!!

Regards.

 

[skymastor]

SOLVED?? Maybe......

Hi Guy's,

Just wanted to give you a quick update on what the craic is so far with this issue...

The following day after I had checked the continuity with the advice given by BlackC55 (thanx BTW), my friend and I decided to swap the wheel sensors around to see if the fault that carsoft was giving would be replicated on the opposite side... At the same time of swapping these around, we cleaned the sensors and the fittings, including the magnetic wheel bearing rings that also make up part of the ABS sensor systems.

After re-fitting and clearing the previous faults, well butter my ass, the problem was solved!!!! No ABS light after 30mph, no ESP, ABS and BAS faults showing in the display! So it appears gentlemen that the ESP/ABS/BAS faults may have been caused by a dirty/incorrectly fitted sensor?? Thoughts please?

As you may be already thinking, having paid a MB main dealer for doing the sensor work and buying a second hand ESP control module and ABS block on their advice that wasn't really required, I will be going to see them next week to point this out! Whats it coming to when you cannot trust a main dealer who are suppose to be the experts on all MB vehicle to do this kind of work?? Unbelievable!!

So far things have been OK and I'm in the South of France with the car, but I will keep you all posted...

Cheers for everyone's help...