RobE55

Soooo driving down the highway. All good. Exit said highway. All good. Take a left on a large expressway. All good. Spirited. Come upon the 6 row of stopped cars - turn lanes full. Press the brake and the dash lights up. **SBC MALFUNCTION VISIT WORKSHOP**

I had NO brakes my friends...NONE. This was for about 2 - 3 seconds of sheer F**K...then the front 2 ***BAM*** lock up and I have everyone looking at me like...???

Pull over and call AAA. I have family at the (st)ealership and the module that controls steering, speed sensing, etc had failed.

Just a heads up to you all that "drive by wire" ----NOT a big fan right now. Always have the plan B ready while driving these beasts.

Rob

AgSilver

Please identify the "module" and can you tell me if you had peddle pressure at all times.

Dublinoh

Good to hear your okay and nobody else involved. When you say drive by wire you are referring to the SBC brakes, correct? Is the module that failed on your car found only on cars that have SBC brakes?

StarvingArtist

Yeh, the more info the better on this sort of thing.

RobE55

OK,

When it happened I had no pedal pressure (or feedback) I just stood on it. Had my left foot on the E brake when the front tires locked up. I'll get the name of the module next week when I pick it up, but I know it does control the speed sensitive steering, ABS, SBC. The steering was SUPER hard after - like the power steering was out. That's how they know it was that module. Usually they said detailers wreck the communication bus spraying it with water (be careful when you clean under the hood) but mine was clean.

More next week my freinds, just a FYI post on my experience

AgSilver

One more question, have all the SBC software/firmware updates been been installed (If you know)?

BoostedAero

+1 for updates... that would be the final straw for my gal

she is not a fan anymore after us getting stranded this weekend by a dead alternator

bbirdwell

RobE55, were you also using the paddle shifter to manually drop the car into a lower gear to use compression braking? This is one of those items that sticks in the back of my mind; catastrophic failure of the SBC system.

I would figure you were tasting seat leather in the back of your throat by the time you got the car stopped...

BoostedAero

He was fighting the car with one hand, stomping on both pedals with both feet and his right hand was up defending blows from his wife whapping at him to slow down and stop the car.

This is something I really look forward to hearing the rest of the story.

I fear my car will suffer from this I have only 60k on actuations on SBC but my car has suffered just about every other ailment so... this will more than likely occur as well!

Update us when we can. Sincerely glad you and your fam are okay!

Yuille36

Well, I very glad this had a positive outcome, because this could have been very ugly. I'm glad you and your family are safe.

BoostedAero

hmmmm... interesting PBKAC failure on my part

RobE55

Not sure on the SBC updates but I will ask. They still have the car. I did get the worst news from the tech --- "your car is fine, we can't re-create the issue" NO WAY JOSE, I said to keep it until you find and fix it. They did - eventually - get the module to fail. So I do feel better about driving it again.

We all have the Plan B in our driving scenarios with cars like this (at least I hope you do) so I had evasive plans in place. Luckily it did lock up the front tires before it went too badly. Downshifting, ebrake, sidewalk & bushes were not needed. The first drive home when I pick it up will be a nervous one for sure.

Rob

rapidoxidation

How did your guy get the module to fail? I'd be recreating those conditions to make darn sure the failure wouldn't be repeated, even if it means flogging the car a bit to do so.

RobE55

OK,

I do know it went up the food chain....and they will keep it and drive logging data for some time.

Sooo a 2017 C300 loaner is putting me around..... BTW there is NO E-Brake in it, foot or hand. Only an electronic one....

Thanks...just Thanks..

Yuille36

And it's not like you can gently apply the E-Brake, to slow a vehicle down....no no! It is applied with full force, so if your were at speed your rear brakes will lock up causing you to slide all over the place, maybe causing an accident in itself. I have this is my Audi, and don't particularly like it

Hulk

MBUSA shouldn't have only a 10 year extended warranty on sbc but lifetime since it can be extremely dangerous!

The system should be programmed that when it is failing car goes into limp mode and brakes are applied slowly to a full stop

Shame on MB!

Blade Canyon

Thanks for that post. Now I need to teach my wife how to hit the emergency brake in case this happens while she is driving.

But keep right foot on the brake pedal the whole time and hope it catches in time?

bbirdwell

When the SBC system fails there are two small emergency valves that pop open; these allow the master cylinder to apply hydraulic pressure directly to the front calipers (and only the front calipers). This is unboosted and the hydraulic pistons are not designed for efficiency. From older posts, one can literally stand on the brake pedal and the front brakes will not lock up.

Using the parking brake and the downshift paddle on the steering wheel are the only other options to assist in slowing down the car. Unless you count the "over the sidewalk and into the bushes" option.

Blade Canyon

Don't forget the "throw the gear shift into PARK at 65 mph" option.

Yuille36

FunkTron

Here here!!!!

FunkTron

......without stopping

Redwood415

SBC woes are really hit and miss, my wifes old E320 with SBC has 290K miles with absolutely zero issues related to SBC or brakes in general. But issues like the one you shared are the reason for the many lawsuits in the early 2000's for W211 and R230 models. knocking on wood right about now.

RobE55

Well,

The only thing that locked up WERE my front brakes!....I must go into "beast mode" when the car does this!

Still no word - I keep checking the CHP & local accident page for my car.

Dublinoh

Sir, you really know your stuff.