Airbags went off for no reason

[richard]

Given lots of airbags went off, then its unlikely it was a failure in a single bag.

Therefore, the airbag unit must have 'decided (by design, or by error -software or hardware-) to ignite the airbags.

If it was design, its because it had a set of factors occur that made it do it. Now either those factors really occured, or it thought they did because of 1 or more sensors failing.

If it was software error, I suspect there would be lots more reported cases.

So, I would put this down to hardware error, with one or more of the airbag controller and/or any/all sensors.

However, if i remember right, the airbag units have a 'control unit log' and do keep info of why/when/what-speed this hapenned at..

So MB dealer really ought be able to find out what sensor triggered it, and should be replacing other stuff (which of course they may be)

What worries me, is that if you don't find out why then it will happen again. I.e some hardware is broken and the same set of circumstances will occur again.

I presume you are talking to your insurance company. Normally airbag deployment == write off.

R

 

[BTB 500]

Therefore, the airbag unit must have 'decided (by design, or by error -software or hardware-) to ignite the airbags.

Again, if a mobile phone at close range can cause a computerised r/c transmitter to misbehave I'm sure it could do the same to an airbag controller. Unless they're screened/shielded?

 

[television]

There is no RF circuits on a SRS system, so phones and the like do not come into this, just shock sensors

 

[glojo]

There is no RF circuits on a SRS system, so phones and the like do not come into this, just shock sensors

That's what common sense tells me but I'm no boffin. When I queried why our air-bags did not go poof.... I was told it needed a significant impact to activate them. The proof of this was the fact that my daughter was in the front passenger seat, and her friend sat directly behind her in the rear seat, these two were exposed to the impact damage of the oncoming Peugeot and neither were injured! Great design technology by Mercedes-Benz.

John

 

[BTB 500]

There is no RF circuits on a SRS system, so phones and the like do not come into this

It's the on-board processors and/or memory that's being affected on r/c transmitters though. It's not an RF interference issue.

 

[television]

It's the on-board processors and/or memory that's being affected on r/c transmitters though. It's not an RF interference issue.

The IR bit only goes to the Eye from then on its just processors

I think it is all a bit hypothetical at this stage,

 

[EJS]

Brief Update

MB dealership has asked for a specialist from MB UK head office to come up and assist in the investigation as their diagnostic tools are coming up blank and they cannot not find any physical reason for the airbags going off.

I am hoping that the specialist can find out why they went off as at the moment I am not haapy to get the car back without knowning why it happened.

I will update again when I hear more.

Thanks for all the support.

 

[Rumpelstiltz]

What happened with this case?

 

[Satch]

Airbags have to act quickly but false firing can ( and has) caused a number of deaths and serious injuries. Modern Airbag ECU's have a quite a bit of intelligence although do wonder about the latest ones with a microwave "pre collision sensors".

However, false initiation of airbags can have quite a mundane source:

General Motors
March 14, 2006

GM Holden has issued a safety recall on specific locally built vehicles from April 2003 to December 2005 sold in Australia and export markets and fitted with side impact airbags as standard or optional equipment.

The recall has been issued following reports to GM Holden that side impact airbags had inflated under circumstances which did not warrant inflation. This may be caused by static electricity charge, generated in particular conditions, which stimulates the airbag inflator if an earthing wire under the seat has come loose.

Such conditions can be generated only when the car is stationary and the person is exiting or has exited one of the front seats, as sufficient charge must be generated and the outer side seat bolster compressed to reach the side airbag inflator.

The situation will be rectified free of charge at Holden dealerships by installing an additional earth spring at the front of each height adjustable seat to correctly earth any charge.

The recall involves 89,167 vehicles in Australia and 34,552 export vehicles for a total of 123,719. Thirteen cases have been reported since 2003 with no resultant accidents - an incident rate close to one in 10,000 vehicles or about 0.01 per cent.

GM Holden Executive Director Engineering, Tony Hyde, today said the organisation had confirmed that the inflation would occur only while the car was stationary, allaying concerns about possible accidents.

“Electrostatic charge accumulation usually requires some sort of moving activity which is generated while swinging out of a seat,” Mr Hyde said. This action also brings the occupant closer to the side impact airbags as the backrest side bolster is compressed when getting out of the seat. The bolster will not be sufficiently compressed while driving to allow any charge to reach the inflator.”

Vehicles impacted by the recall comprise those built between April 1, 2003 and December 2, 2005 with side impact airbags as standard or optional equipment.

 

[280gee]

“Electrostatic charge accumulation usually requires some sort of moving activity which is generated while swinging out of a seat,” Mr Hyde said.

Electrostatic charge also accumulates between a human body and certain types of clothing, also between a clothed body and the seating, due to normal vehicle motion.

Moving toward an earthed surface or one at a much lower potential allows a dissipation or sudden discharge of that accumulation. e.g. The recognisable to some "zap" when climbing out of certain cars.

Electrostatic precautions will be a familiar thing to anyone involved in handling explosives and maybe airbags?