2001 Civic EX - driver airbag fails to deploy but passenger does

I regret to say one of my wife's co-workers was involved in fairly serious
car accident over this Canadian Thanksgiving weekend in her 2001 Civic EX.
Fortunately, she was not seriously injured and was travelling alone.
However, car did not fare so well.

From what I understand, she was making a left turn when someone hit her on
the front left fender - hard (I'm not sure of the logistics of how that came
about...). Anyway, the front end was pretty mashed up.

But here's the alarming part - the passenger airbag deployed... but the
driver side did NOT. (!?) I realize the impact is not the ideal type to
trigger and make use of airbags, but the fact that only one of them deployed
is a little disturbing. Is this the way the airbag in this car are
designed, or do we have a faulty driver airbag on our hands??

I was under the impression that they are both on the same switch - so either
both deploy or neither do. Or perhaps alternately, there may be a "weight
sensor" of some sort on the passenger seat to detect if there is a passenger
and deploy accordingly - but regardless, there should never be a situation
where the passenger side goes off but the driver does not...???

That being said, in the grand scheme of things, this case was probably for
the best that the driver side did not deploy, as the driver is a rather
short individual, so she sits fairly close to the steering wheel in order to
reach the pedals... but it's still disturbing to think that this expensive
safety device may have been defective.

Or am I totally off on my understanding of how most airbag systems work?

Thoughts?

Thx!


Kevin

 

Here`s my input on the logistics. see below.

The sensor designed to pick up the front left impact may be the
mercury type. If this sensor is located at the left bumper and becomes
destroyed and car speed is under say 15mph, the control unit could
possibly play it safe and won`t deploy based on two more mercury
sensor in the cockpit.

On the right side, however, is not destroyed in the crash and this
sensor senses the car moving backward with great force.

I agree. When working on a 2001 Civic EX left front crumpled bumper
two days ago, I noticed a sensor which I believe is for the airbag
sensor, indicated by yellow connection labled `sensor` as I recall. I
did not confirm this yet, but it`s a design flaw. The left bumper
frame design to protect the sensor is made to crumble into the sensor
much like an eggshell into a yoke. I wouldn`t design it this way. I
would have protected the yoke to withstand impact for at least 1.5
seconds. If anyone has a 2001 Service Manual, where is the farthest
sensor location? Thanks.
K

 

the drivers airbag didn't deploy because she was wearing her
seatbelt. the passengers did because the belt was not fastened and
there are no sensors to determine if the seat is occupied. it worked
just like it should have.
as for the clown that thinks the sensors should wait 1.5 seconds.
well by then the accident is over and you have dead people. Not a
real smart choice.....
Chip

 

As for the [person] that thinks the sensors should wait 1.5 seconds.

Outboard sensors should be protected and operational for at least a
second.

`Within milliseconds of a crash (1/1000 of a second) the Personal
Safety System is in action. Let`s follow the system through a crash.

Approximately 6-8 milliseconds -- Sensors detect that a possible crash
is occurring.

Approximately 8-12 milliseconds -- Sensors determine rate of
deceleration (crash severity), position of driver`s seat and whether
front-seat occupants are wearing safety belts.

Approximately 12 milliseconds -- Restraint Control Module sends signal
to pretensioners and air bags (go/no go -- depending on crash
severity).

Approximately 12-20 milliseconds -- Pretensioners take up slack in
belts, "restraining" front occupants and holding them in the proper
position for airbag deployment

Approximately 30-50 milliseconds -- The airbags are in position to
help restrain occupants Energy management retractors start to slacken
belt to reduce belt pressure on chest and allow front-seat occupants
to move toward the airbags `

To clarify,

`The Front Outboard Safety Belt Usage Sensors monitor whether the
driver and right front passenger are buckled up. At higher speeds,
airbags need to deploy with greater pressure if passengers haven`t
buckled their safety belts. At lower speeds with safety belts
buckled, airbags can deploy with less pressure, helping to reduce the
risk of airbag-related injuries.

The Personal Safety System Restraint Control Module (RCM) is a
sophisticated computer located under the instrument panel at the front
edge of the passenger compartment. The RCM receives signals from the
electronic crash-severity sensor, located at the front of the vehicle,
and judges how fast the vehicle is decelerating. It also processes
signals from the other Personal Safety System sensors and determines
how the dual-stage front airbags and safety belt pretensioners will
deploy

In less severe frontal crashes, airbags inflate with less force or not
at all helping to reduce the risk of injury due to the inflation of
the airbag. The system helps to make sure the appropriate level of
airbag pressure is used.`

The quoted statement is borrowed from 2001 Ford Tuarus Saftey Guides.
K

 

Thanks for the info, Koji and Chip!

So, to summarize, the ABS systems detects whether the seat belt is
connected and how severe the impact is and deploys the airbag
accordingly? This would make sense, as it was not a *terribly* high
speed impact (and she was wearing her seatbelt AFAIK) and there was no
passenger.

One thought though - Koji, you quoted a statement from a 2001 Ford
Taurus guide... do we know for certain whether it is the same or
similar system in the 2001 Civic?

Thanks again,

Kevin

 

the drivers airbag didn't deploy because she was wearing her

Up here, in Canada, the seatbelts are mandatory and the airbags deploy when
the seatbelt is fastened.
As far as I know, an airbag is not a substitute to the seatbelt.

 

the civic continually monitors seat belts, it doesn't just make the
call at the time of impact. the front crash sensors are of the piezo
crystal type. it's electrical, which is very close to the speed of
light .
this is different than a ford. i've worked on both.
as for pre-tensioners, it depends on the crash also. i've seen
buckles deploy and not belts.
Chip

 

`The Front Outboard Safety Belt Usage Sensors monitor whether the

Yes. And under severe crash, her bag may deploy, thus injuring her but
not killing her. Many newer vehicles now have solid state crash
sensors that contain either a piezoelectric crystal or a
"micromachined accelerometer" chip that produces an electronic signal
when jolted. My previous statement about these sensors being
inoperative, such as ripping the sending wire during a crash is
unlikely.

Honda has been an early adopter of dual stage, dual threshold air
bags, they're pretty much the same.

http://www.nhtsa.gov/cars/testing/ncap/cars/1689.html

K