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BMW Mini 2004 - Drivers seat side airbag deployed with no impact #

Posted by Martin Kelly on March 19, 2011, 9:16 pm

Year of Manufacture *: 2004

Hi, customer rang me say her drivers seat side airbag suddenly went off when driving on a straight road with no bumps etc. and it frightened the life out of her.
She's going to ring BMW Mini on Monday but in the meantime has anyone heard of or had experience of this before?
By code reading the airbag control unit will it tell me what triggered the airbag?

Martin.

Re: Mini 2004 - Drivers seat side airbag deployed with no impact

Posted by aidan <iframe src='https://members4.boardhost.com/ukautotalk/info/user=UKAT2879' width='330' height='300' border=0 style='border:none;'> on March 19, 2011, 11:20 pm, in reply to "Mini 2004 - Drivers seat side airbag deployed with no impact"
Aidan Birley

Hi

I have a rover here with driver seat air bag deployed and owner says he was on a straight road and did not hit any thing.

It also has two flat tyre on on the driver side both with side wall damage.

now that's what I call an unexplained coincidence.

May be worth having a look for tyre / rim damage

Re: Mini 2004 - Drivers seat side airbag deployed with no impact

Posted by Graham Bullock <iframe src='https://members4.boardhost.com/ukautotalk/info/user=UKAT2744' width='330' height='300' border=0 style='border:none;'> on March 19, 2011, 11:27 pm, in reply to "Re: Mini 2004 - Drivers seat side airbag deployed with no impact"
Graham Bullock

Can the control unit set off individual airbags? Or would they all be set off (except those illiminated by seat occupancy switches)?

Graham

Re: Mini 2004 - Drivers seat side airbag deployed with no impact

Posted by Matt Booth <iframe src='https://members4.boardhost.com/ukautotalk/info/user=ukat3028' width='330' height='300' border=0 style='border:none;'> on March 20, 2011, 7:43 am, in reply to "Re: Mini 2004 - Drivers seat side airbag deployed with no impact"
Matthew Booth

Yes individual airbags are set off depending on where the vehicle detects an impact. It has to pick up 2 crash signals but they don't have to be at the same time. For instance if she's had a previous bump on a corner that upset one of the satellite sensors that would be one crash signal. If she then at any time in the future went up a kerb too hard or hit a big pot hole it could trigger another sensor which would then set off an airbag.

The X5 suffered this as people used to bang them up kerbs. The ABS ECU is by the handbrake so if they let the handbrake off to hard it would set the airbags off.

In short, she'll get nowhere with MINI. They can however tell what caused the system to go off.

Matt

Re: Mini 2004 - Drivers seat side airbag deployed with no impact

Posted by Martin Kelly <iframe src='https://members4.boardhost.com/ukautotalk/info/user=UKAT2863' width='330' height='300' border=0 style='border:none;'> on March 20, 2011, 6:35 pm, in reply to "Re: Mini 2004 - Drivers seat side airbag deployed with no impact"

Matt,
"The ABS ECU is by the handbrake so if they let the handbrake off to hard it would set the airbags off."
Did you mean the Airbag ECU?

Martin.

Re: Mini 2004 - Drivers seat side airbag deployed with no impact

Posted by aidan <iframe src='https://members4.boardhost.com/ukautotalk/info/user=UKAT2879' width='330' height='300' border=0 style='border:none;'> on March 20, 2011, 6:54 pm, in reply to "Re: Mini 2004 - Drivers seat side airbag deployed with no impact"
Aidan Birley

Hi

>>>>>> It has to pick up 2 crash signals but they don't have to be at the same time <<<<

Matt I find that had to belive i.e that the signals do not have to relate to the same impact.

Cheers Aidan

Re: Mini 2004 - Drivers seat side airbag deployed with no impact

Posted by Tommy Forrest <iframe src='https://members4.boardhost.com/ukautotalk/info/user=UKAT1706' width='330' height='300' border=0 style='border:none;'> on March 20, 2011, 7:58 pm, in reply to "Re: Mini 2004 - Drivers seat side airbag deployed with no impact"
Thomas Forrest

My understanding of SRS systems is that the power source going to the squib on an airbag system goes through a "safing sensor" which is a switch that closes at a pre set deceleration rate. Therefore the vehicle must be decelerating at a certain rate along with an impact sensor signal to initiate the airbag to trigger.

Probably doesn't explain why the side airbag went off, but it should only have triggered if both an impact sensor and the safing sensor were activated at the same time.

Tommy

Re: Mini 2004 - Drivers seat side airbag deployed with no impact

Posted by Matt Booth <iframe src='https://members4.boardhost.com/ukautotalk/info/user=ukat3028' width='330' height='300' border=0 style='border:none;'> on March 20, 2011, 10:00 pm, in reply to "Re: Mini 2004 - Drivers seat side airbag deployed with no impact"
Matthew Booth

Sorry I did mean airbag ECU.

Aidan it is indeed correct i'm afraid. One of my jobs at BMW UK was thermal incidents and airbags. This involved a lot of MINI and X5 cases regarding airbags, and various other design flaws! The side airbag needs to detect an impact from a satellite sensor and the MRS control unit.

The crash telegrams can be checked and will give reason for why the airbag deployed and the system time that the sensor detected the crash...or not as the case may be!

This is not an unusual case. Many unhappy MINI owners...E46 owners...E53....

Matt

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