BMW series 5 disables Dynamic Stability Control and ABS

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no.one@no.gov - 29 Nov 2004 17:56 GMT

Date: Mon, 8 Nov 2004 23:59:42 +0100 (W. Europe Standard Time)
From: Stefan Lesser [redacted for spam control]
Subject: BMW series 5 disables Dynamic Stability Control and ABS
(originally posted in comp.risks)

After two accidents involving police cars of Berlin, Germany, at first the
drivers were blamed and appointed to a security training. But taking into
consideration the driver's nearly identical reports, which claimed that the
cars on-board drive dynamic control systems 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 ditto):
http://www.autobild.de/aktuell/neuheiten/artikel.php?artikel_id=7348
http://www.autoservicepraxis.de/sixcms4/sixcms/detail.php?id=81192&_topnavi=3245
4&_zielcb=

Stefan Lesser, Muenchen, Burda Digital Systems GmbH, Am Kestendamm 2,
77652 Offenburg, Germany +49 89 9250-3433 http://www.burdadigital.de

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Jeff Strickland - 29 Nov 2004 21:14 GMT

> Date: Mon, 8 Nov 2004 23:59:42 +0100 (W. Europe Standard Time)
> From: Stefan Lesser [redacted for spam control]
[quoted text clipped - 9 lines]
> and can only be re-enabled by switching off the ignition for five
> seconds...

Let me see if I understand, if the driver makes an emergency stop - or
similar type of manuver - the vehicle control systems can disable themselves
without warning the driver this has happened, then in a subesquent manuver
where the driver might be relying on the features, he might find them not
available? That seems like a problem that should require immediate response
from BMW.

As much as I think the vehicle control systems should always work, if they
are turned off for any reason, including but not limited to driver
selection, the driver should be informed that the features are not currently
available. All this means is that a light should turn on if the vehicle
control systems - ABS and Traction Control - have either been switched off
by the driver, or have gone off for some reason that only the car knows
about.

> Originating report (German only):
> http://www.daserste.de/plusminus/beitrag.asp?iid=254
>
> Follow-Ups (German ditto):
> http://www.autobild.de/aktuell/neuheiten/artikel.php?artikel_id=7348

http://www.autoservicepraxis.de/sixcms4/sixcms/detail.php?id=81192&_topnavi=3245
4&_zielcb=

> Stefan Lesser, Muenchen, Burda Digital Systems GmbH, Am Kestendamm 2,
> 77652 Offenburg, Germany +49 89 9250-3433 http://www.burdadigital.de

Reply to this Message

James C. Reeves - 30 Nov 2004 00:53 GMT

| > Date: Mon, 8 Nov 2004 23:59:42 +0100 (W. Europe Standard Time)
| > From: Stefan Lesser [redacted for spam control]
[quoted text clipped - 26 lines]
| by the driver, or have gone off for some reason that only the car knows
| about.

Let me see if I understand the basics of what is happening here. The stability
control systems are really doing virtually nothing to improve safety...only
allowing the driver to push the car to it's new edge, which they are doing. No
wonder the HLDI's FAQ page on simple ABS system says that insurance loss data
shows NO REDUCTION in accidents (comparing insurance loss statistics of cars
with ABS with cars without ABS). Apparently what so many have said is true!!!
These systems just allow drivers to push the envelope further and does nothing
to actually improve safety "per-se".

Reply to this Message

Jeff Strickland - 01 Dec 2004 01:46 GMT

> | > Date: Mon, 8 Nov 2004 23:59:42 +0100 (W. Europe Standard Time)
> | > From: Stefan Lesser [redacted for spam control]
[quoted text clipped - 35 lines]
> These systems just allow drivers to push the envelope further and does nothing
> to actually improve safety "per-se".

Keep in mind the drivers in the report were police, so they are more likely
to approach "the edge", and remain there more often and longer than the rest
of us mortals. And, by my reading, the problem the police had wasn't that
the systems let them down, the problem is that the systems shut off, so the
police were thinking a behavior they had trained for would occur, but the
fact is it didn't occur at all. In short, the police drivers expected
something to happen that did not happen, and the result was apparently a
wreck.

The report made no mention that I can recall of civilian drivers having
these issues. This doesn't mean civililan drivers haven't had them, but it
is possible that the trouble is related to the police spec that the cars are
built to. But, it seems to me that the systems worked fine, then shut off
for some unknown reason, and it is this shutting down without any indication
that is what needs to be fixed. The system should not shut down unless the
driver turns it off, and if it does shut down with or without driver input,
the driver should be told that the system is inactive.

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Rick DeBay - 01 Dec 2004 04:37 GMT

[snip]

>The report made no mention that I can recall of civilian drivers having
>these issues. This doesn't mean civililan drivers haven't had them, but it
>is possible that the trouble is related to the police spec that the cars are
>built to.

[snip]

One civilian driver did state he experienced the problem, but it was not
verified by a BMW mechanic:
'Few days ago with Krefeld. Volker A. is with its BWM 525 Touring, type E 39, on
the way. After a vollbremsung ESP and DSC switch off. The flares do not go out.
Volker A. tells: "I was forced to make a vollbremsung with this vehicle, and
there I had to brake up to the stop. And all warning lamps are sudden in the
system on and remain also on, those do not go out thus. Now I looked up times
degrees in the manual, and there there is simply a reference that the brake is,
but the systems evenly no more, and one from the BMW service examined to have
that normally still functioned."'

The problem was fixed on the police cars with a software update, but no recall
is planned.

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Rick DeBay - 01 Dec 2004 04:29 GMT

The system expects braking forces of only 150 to 200 pounds to be used during
braking. If it senses 265 pounds, it shuts down. The problem is that up to 330
pounds can be applied during an emergency stop (from the translation).

I've seen drivers large enough that they could apply this much force easily.
How long until a US recall?

Babelfish translation links:
http://babelfish.altavista.com/babelfish/tr?url=http%3A//www.daserste.de/plusmin
us/beitrag.asp%3Fiid%3D254&doit=done&tt=url&intl=1&lp=de_en
http://babelfish.altavista.com/babelfish/tr?url=http%3A//www.autobild.de/aktuell
/neuheiten/artikel.php%3Fartikel_id%3D7348&doit=done&tt=url&intl=1&lp=de_en
http://babelfish.altavista.com/babelfish/tr?url=http%3A//www.autoservicepraxis.d
e/sixcms4/sixcms/detail.php%3Fid%3D81192%26_topnavi%3D32454%26_zielcb%3D&doit=do
ne&tt=url&intl=1&lp=de_en

>Date: Mon, 8 Nov 2004 23:59:42 +0100 (W. Europe Standard Time)
>From: Stefan Lesser [redacted for spam control]
[quoted text clipped - 19 lines]
>Stefan Lesser, Muenchen, Burda Digital Systems GmbH, Am Kestendamm 2,
>77652 Offenburg, Germany +49 89 9250-3433 http://www.burdadigital.de

Reply to this Message

Ramone Cila - 01 Dec 2004 18:02 GMT

> The system expects braking forces of only 150 to 200 pounds to be used during
> braking. If it senses 265 pounds, it shuts down. The problem is that up to 330
> pounds can be applied during an emergency stop (from the translation).

I think something else is also at play here. Applying 260 or 330 pounds on
the brake pedal is a pretty high threshold (I don't care if you do sled 800
lb. in the weight room). The angle of the leg and position of the driver
body make that threshold pretty hard to reach. It is more likely that the
car was already in some difficulty and the addition of forward body momentum
and leg braking, applied the high amount of pressure to the pedal (the
proverbial "standing on the brake" scenario). And it may be that once the
car is already in that amount of trouble it is proper for the stability
systems to be off, as they may not be mapped to work correctly or securely
under those extreme conditions. Just a guess, but I don't think it is as
simple as pushing the pedal to the tune of 260 lb. of pressure or that the
260 lb. is an arbitrary threshold.

If memory serves me well, (and at my advanced age it sometimes doesn't :^)
all stability systems on all current cars have a shut off point. Some work
from pitch and yaw, others from rotation, still others from simple G force,
and maybe some combination of each or all. I am certain that BMW's systems
shut off from more than just this one dynamic (brake pedal pressure).

This whole thing about the police though, reminds me of when ABS first hit
the market. Police all over the country were getting into accidents because
they had been trained to pump brakes...and of course pumping ABS in those
days was tantamount to asking for lose of vehicle control.

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