SBC and NHTSA
 

NHTSA and SBC
I have been in contact with the NHTSA regarding the SBC service threshold issue. They advised me to have as many owners of vehicles with these units to contact them via safercar.gov and file a complaint. This is only way the NHTSA will take any action.

This is a safety issue since the brakes go into backup mode with no prior warning. At the very least MB should issue a recall to interrogate the units with STAR DAS.

Thanks for your help.

John

Below is what I submitted to the NHTSA website. It will ask for date of incident, but just use the date you file.

This vehicle is equipped with Sensotronic Brake Control that has a service threshold. When this threshold is reached the brake system defaults to non power assisted hydraulic mode to the front wheels only. This occurs without any prior warning and results in increased stopping distance. I have sent a copy of the Mercedes service bulletin S142.46-P-0012A which addresses this issue. Mercedes stopped installing this system in 2006. At the very least, Mercedes should issue a mandatory recall to interrogate these vehicles with STAR DAS to determine how close to the service threshold the SBC unit is and replace them at the dealer's expense. This is a major safety issue that needs to be addressed.
https://mbworld.org/forums/images/st...ser_online.gif https://mbworld.org/forums/images/cu...ns/forward.gif

Yes I totally agree. I just had to replace my SBC about 6 months ago.....easy $1,800 :X

As a 2006 Canadian E350 owner, can I file with NHTSA?
Thanks,
MBEdw

I don't know, but you can try and file it.

Complaint has been filed with the NHTSA:

When attempting to exit the highway, the Sensotronic Brake Control system (SBC) failed and there were no noticeable brakes. The pedal went all the way to the floor with no resistance. Manufacturer claims that if you apply additional pressure during a failure, there will be some braking power available. In the situation though, when the pedal goes to the floor, human instinct is to immediately find an alternative way to stop the car. I was able to stop by downshifting the transmission and applying the emergency brake. Less experienced drivers may not be so lucky.

Mercedes Benz USA is aware of the potential for all SBC electric pumps to fail at any time causing this same situation for anyone. They are unwilling to cover the defective part because I am 1 month beyond the 'extended warranty.' They claim that as with any car parts, the SBC system can be expected to fail at some point. Anything beyond 10 years and they do not take responsibility for. Normally I would agree with that sentiment, but not when it concerns the primary electric system of electric brakes to fail. There should at least be a sufficient AND NOTICEABLE hydraulic back up if this part is engineered to fail.

Mercedes has recently extended all fuel tank related issues and components to 15 year coverage, and this would at least be a step in the right direction for the SBC system. However, I believe Mercedes Benz USA and the NHTSA should mandate a recall of all vehicles equipped with SBC to be inspected yearly and replaced free of charge for the life of the vehicle. I believe it is just a matter of time before there are significant deaths or injuries due to this problem - as the affected vehicles are all about 10 years old at this point. It is a valid concern for both me as a driver of an affected vehicle, and a concern for fellow motorists and pedestrians on the road.

Agreed. The chilling thought is that not only are you risking your death in these cars but the death of others. One could make an argument for negligence on the owner's part for even taking an SBC equipped vehicle on the road!!! Our E320 wagon is at the dealer for the gas tank replacement but it will NOT be going back on the road until I have a written guarantee from the dealer that the SBC system will not 'end of life itself' while we are out driving it.

We will all be very interested if your dealer will give you this written guarantee. I have scheduled the recommended 2yr brake flush and have requested the dealer interrogate the SBC with STAR system to determine how many activations have occurred. If close to the limit, the SBC will be replaced. My 10 yr warranty is up in August.

John

Let me know how this works out for you, RCPDesigns. Judging off your info there, if your e320 is a 2004, I almost guarantee your dealer won't do anything for you. My failure was on 2/20 and 10yr warranty was up on 1/6 in my 2005. Dealer and MB USA hasn't helped at all. We are now on day 10 of my car sitting at the dealer probably collecting door dents.

I am still absolutely astounded that the system was designed in such a way. If a service limit is required then it should predict approximately when that limit would be reached and start notifications MONTHS in advance and then refuse to start once reached. This kind of design failure destroys the confidence I once had in Mercedes. I pay more for a Mercedes to protect the ones I love... not to purposefully shut down a braking system and leave them barreling down the highway hoping that they can figure out how to stop the car. Directing a braking system to shut itself down for reaching an arbitrary service limit during operation is reckless endangerment.

Here's a copy of the document regarding the service limit. File with NHTSA.

John

Got the wagon back and to no one's surprise... no commitment from MB on the SBC. They first claimed that they could not interrogate the SBC and that there wasn't a service limit. I referenced the service bulletin and included the above copy of the document. The SA then checked with the foreman who said that they could interrogate the SBC but it would only be pass/fail... not a number that could make a prediction on amount of life left. I've got some work to do on the car this weekend (engine mounts) and I'll have a look with SDS and see what I see. Both my Indy and the Dealer say that the reports of my fellow forum members are incorrect, that sudden loss of braking doesn't happen that everyone would have gotten a warning days in advance. Considering they are sitting in an office and my fellow members were sitting behind the wheel... I think I know who to believe.
I'm gathering a paper trail on this because I believe the SBC warranty will be extended in the future... but I'm pretty sure I'm going to have ours replaced now. My SA was talking about something in the $1500 range. If I can get them to do it for $1000 or so then I'll do it.
The Wife and I have gone over how to stop the car by downshifting, right foot on main brakes, left foot on e-brake with left hand holding e-brake release. Hoping it never comes to that.

Now that the warrantys have expired this would be a good time for a group buy.

Mine does not expire until August 2015, but here is a MB dealer online price.

http://huskerparts.com/parts/2006/Me...&siteid=215771

John

Great Link This replacement would be a great wiki topic or is it covered in wis already

Just returned from MB dealer after SBC brake flush, $179 including fluids. They told me that there is absolutely no way to know how many
SBC activations have occurred or how many the unit has left before the service threshold is reached.

It seems a few lines of new computer code could provide a warning at a predetermined limit.

I plan on contacting MB customer service again with this suggestion. Most likely it is going to take a fatality related to system failure and a lawsuit before anything changes.

John

first of all, when the threshold is reached there is no failure. its the same as when you get a brake wear warning, they are telling you this is something that needs to be looked at soon. its MEANT to scare you so you dont sit on your laurels.

i dont know why people think it loses all hydraulics. the case above of the guy who lost all his brakes has nothing to do with the service threshold being reached, it has to do with an internal failure! the threshold code is to head off a potential future failure. his issue is different. the pressure accumulator is there for this reason. start car, pump runs and builds up pressure, accumulator holds pressure. as that pressure is used up, the pump runs again to build it up. thats why you hear it run all the time.

if the pump fails, the accumulator lets you have brake assist. if the accumulator fails, then you'd better hope the pump still runs. either way you get a different code than c249f.

sds only tells you either its good or bad, there is no way to see exactly how many cycles it has run that i know of. maybe a developer mode but the dealer techs dont have access to this.

this will not end in your favor IMO unless you can prove premature failure of a safety orientated part, which reaching a predetermined threshold is not. that red warning IS your early detection....

$1000 part for 10 years, equals $100 a year....well within acceptable maintenance requirements for a vehicle. this will not end in your favor IMO. my car is out too, oh well, thats the price you pay for technology, cash in hand ready to replace my sbc unit when it calls for it. i take this puppy up to 155 every so often, my life is worth more than $1000, at least to me lol

No.

I received the warning as well and there was MAYBE 2% braking capability remaining. That's with the pedal on the firewall, I track cars and am more than familiar with the braking capabilities of most cars. For the first time in my life I hesitated (after a short test drive) and decided NOT to drive to work (and I have driven in some very sketchy circumstances). Even with force enough to push the pedal into the firewall it was still a gradual slow down. This was at around 5 MPH!
Now imagine coming off a steep offramp from 80mph that ends abruptly and perpendicular to a busy intersection when this happens... NOT GOOD.

Here is the best part, After sitting in the car off for a few minutes thinking about how I would get to work, I decided to start the car up again, the message was gone and full braking pressure restored!
Talk about a game of Russian Roulette, I have no idea when this time bomb is set to go off again and I have a 500 mile round trip coming up this weekend!

This is not even remotely acceptable.

Proctor was M/Y are you talking here.

If you have 2% plus E brake it is better than nothing

MY2005. Listen I understand there is a failsafe and when combined with the E-brake and tapping your head and rubbing your tummy it gives you the ability to stop as well as a fully loaded 18 wheeler.
But this is simply dangerous on all counts. The two most important things in a car are Brakes and Visibility! You can not eff those things up or you are asking for trouble.
Standard brakes just don't fail like this, a bad booster or ruptured line maybe but it's still gradual and most cars rarely get to that stage (notice vacuum leak etc albeit im in a diesel).

You can't have a braking system that just cuts out without warning like that, it has no clue what your circumstances are when it happens which is a recipe for disaster (see above scenario).
If I could I would retrofit a standard braking system on this car but it would require heavy modifications and frankly Mercedes should just own up to this (since they moved on from SBC) and just replace them as they go bad. Chalk it up as a loss in the R&D department and a premature backing of unproven technology. They can afford it, I can't...

We all know that regular brake systems can fail without warning as others have stated. What I believe is different with the SBC system is that it can have a decrease in braking power to 5% of normal due to a pre-programmed end of service life! According to several owners, this has occurred without any prior warning.

Please file your complaint with the NHTSA as outlined at the beginning of this thread.

John

The more owners work it out with dealers the more "mb will be to the customers" which is me and you in the long run.

More Guv is not always good

Yes regular brake systems can fail and STAY FAILED. The only thing even comparable to this would be a master cyl going out and even then you can pump the brakes and have much more ability to stop. I've had it happen and even in a box truck with air brakes (torn boot) and I would take both over an SBC failure any day.
Although they fail mechanically, not because of some computation that tells it that it should go into fail safe mode.
And speaking of that "fail safe" mode:

(http://www.benzworld.org/forums/w211...ne-wild-4.html)

You can not compare an SBC failure to anything in a standard system. The way it fails, why it fails, lack of warning, possible inadequate shutoff valve, expense of repair, lack of indication of part wear.. etc



I filed my complaint before my first post, but thanks for the reminder.

Does anybody know why the fail condition (often?) ends up being worse than regular brakes with no hydraulic support (e.g. engine not running and pressure used up)?

Check that thread i linked to. Some fluid engineers talking about it with sbc schematics. Im very curious about the shutoff valve and if this explains the inadequacy.

Has anybody developed a retro fit to the my 07+ system or any sort of standard hydraulic abs system retro fit?