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After two accidents involving E39 police cars of Berlin, Germany, at first the drivers were blamed and forced to take driver training. But taking into consideration the driver's nearly identical reports, which claimed that the cars on-board drive dynamic control systems (DSC) had failed, BMW took on and inspected the case. The result was: Yes, after an emergency brake exceeding a certain preset pressure on the pedal, all stability systems are disabled and can only be re-enabled by switching off the ignition for five seconds...

Originating report (German only):
http://www.daserste.de/plusminus/beitrag.asp?iid=254

Follow-Ups (German only):
http://www.autobild.de/aktuell/neuheiten/artikel.php?artikel_id=7348
http://www.autoservicepraxis.de/sixcms4/sixcms/detail.php?
id=81192&_topnavi=32454&_zielcb=

I presume this applies to all E39s with DSC, including the M5. Apparently the system is designed to shut down when brake pedal pressure exceeds 120 kilograms of pressure during DSC activation, which the system believes is a malfunction. BMW is not issuing a recall.
(I used the Google language translation, so hopefully I understood what was written. Perhaps some of our native German speakers can confirm.)

- Dave
 

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FlyM5 said:
After two accidents involving E39 police cars of Berlin, Germany, at first the drivers were blamed and forced to take driver training. But taking into consideration the driver's nearly identical reports, which claimed that the cars on-board drive dynamic control systems (DSC) had failed, BMW took on and inspected the case. The result was: Yes, after an emergency brake exceeding a certain preset pressure on the pedal, all stability systems are disabled and can only be re-enabled by switching off the ignition for five seconds...

Originating report (German only):
http://www.daserste.de/plusminus/beitrag.asp?iid=254

Follow-Ups (German only):
http://www.autobild.de/aktuell/neuheiten/artikel.php?artikel_id=7348
http://www.autoservicepraxis.de/sixcms4/sixcms/detail.php?
id=81192&_topnavi=32454&_zielcb=

I presume this applies to all E39s with DSC, including the M5. Apparently the system is designed to shut down when brake pedal pressure exceeds 120 kilograms of pressure during DSC activation, which the system believes is a malfunction. BMW is not issuing a recall.
(I used the Google language translation, so hopefully I understood what was written. Perhaps some of our native German speakers can confirm.)

- Dave
Maybe someone can enlighten me...

Why would DSC "shutdown" necessarily cause an accident? Do the brakes quit functioning?
 

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Lscman said:
Maybe someone can enlighten me...

Why would DSC "shutdown" necessarily cause an accident? Do the brakes quit functioning?
I seem to recall from the article that the antilock system shuts down as well. So while the brakes still work, the driver locking up the brakes would lose steering control.

- Dave
 

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Interesting...

Since I can't read German, anybody know DOES THE DSC (and ABS?) LIGHT ILLUMINATE WHEN THE SYSTEM DISABLES?

This would seem to me to be a key factor in determine if a recall will be coming.

ard
 

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From the owners manual:

If DSC light blinks while driving, it is helping control of vehicle.

If you press the DSC button and the light stays on you have manually overidden the DSC system. (Fun mode-fishtails galore).

If the light comes on and stays on, and you have not pressed the DSC button === Problem.
 

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jjc1843 said:
From the owners manual:

If DSC light blinks while driving, it is helping control of vehicle.

If you press the DSC button and the light stays on you have manually overidden the DSC system. (Fun mode-fishtails galore).

If the light comes on and stays on, and you have not pressed the DSC button === Problem.
Right.

But the question is, FOR THIS SPECIFIC DEFECT/SCENARIO, does the DSC light illuminate when it 'shuts down'?

My reasoning is if the DSC disables but tells the driver there is a 'problem' it should not warrant a recall. If however, it 'fails silent' and DSC is off an you do not know- that is a problem. Additionally, if ABS is disabled the driver must be informed.
 

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I'm now seeing a similar behavior, first experienced after a quick stop with lots of pedal pressure on a steep downhill. The DSC light on the dash went on at the bottom of the hill and some brisk acceleration confirmed that the DSC was now off. 5 seconds with the ignition cleared it until this morning.

I went to pass someone on a wet road and the rear end fishtailed badly and the light went on again... DSC failure.

Regardless of whether the light comes on or not, it may be too late, especially in a slippery situation like I was in this morning. A little reverse lock on the steering got me out of my predicament, but if the failure is unpredictable, then how can you really drive the beastr at even 8/10ths without the risk of failure that will put you in a ditch?

Anybody talked to a dealer about coverage for this?

allan
 

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I drive with nannies off, so that is less of an issue for me. But even with systems like DSC it is very important to be able to handle the car at 8/10ths with DSC off before you have at it on the backroads. Track time is helpful.
However, I dont know if DSC would store any faults, so it might be interesting to see what the dealerships end up doing.
:cheers:
 

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Bren,

Completely agree with your comments regarding knowing how to drive the beast without the DSC, and I attribute my reverse lock reflexes this morning to time without it on.

I've found, however, that crappy roads + rain + DSC = faster/safer driving, but NOT if I cant expect it to work reliably. Earlier in the thread, Ard postulates that if the light goes on, BMW is covered from a liability standpoint, but I don't agree if it only comes on right when you need it the most.

allan
 

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Allan- sounds like you are comparing apples and oranges....

If DSC is enabled and you enter a situation where the car computer intercedes to attempt to avoid a 'situation', the light comes on... this is not "DSC Failure" as you note. It is DSC acting. It *should* prevent handling issues- but in you case it is not- perhaps a sensor failure or system problem of the garden variety.

Do you think you exceeded 120 kg of pedal pressure? (264 lbs force) Did the DSC light stay on when DSC was inoperable?

This specific failure mode is triggered by way high brake force. Are you seeing this consistantly?

We've never determined if the light is related to the falure in germany... and I agree that a DSC light coming on as the dsc fails to protect is worthless.

a
 

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Thanks Ard,

Your comments are right on regarding DSC in normal operating mode, when it normally protects me from myself ;-}

The first time that DSC failed was coming down a steep grade outside of Sutter Creek with high pedal pressure. Since then, I've gotten the light to come on and stay on in other situations where DSC would have been invoked (one braking situation with light pedal pressure and one episode with acceleration) Once the system resets, I've tested the DSC in controlled settings and it has worked fine, only to fail again later.

One interesting note is that I am likely in need of a front brake pads, and wonder if sensors are out of adjustment if little pad material is left.

Where in the foothills do you hail from?

allan
 

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IMHO it sounds like you may have a DSC operating issue unrelated to the specific '120kg brake force sysyem shut down scenario' discussed in the press.

Be interested to hear what the dealer can do, as far as faults and history stored. (We are very interested to know what they can recall from the memory...)

Yes, I did note your name and city...I suspect you have a rare beast in your neck of the woods. I am northwest of you a bit- look for a PM
 

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Problem solved.....

Had to document for the archives

I was ready to head to the dealer when I got an ominous "brake fluid low" warning.... the brakes are near the end of their service life, so I top the fluid off and sure enough, the DSC stops popping off. Has not come on since.... go figure...

allan
 

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Yeah, low level of brake fluid would cause the DSC system to shutdown. make sure you remember to take some of the fuids out when you install new brake pads or you might have a mess in the engine compartment.

volcanom5 said:
Problem solved.....

Had to document for the archives

I was ready to head to the dealer when I got an ominous "brake fluid low" warning.... the brakes are near the end of their service life, so I top the fluid off and sure enough, the DSC stops popping off. Has not come on since.... go figure...

allan
 
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