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The MAZDA3 and 2005 Tribute have one of the most advanced front airbag systems in the industry. Designed to maximize driver and front passenger protection while minimizing the risk of air bag related injuries, each front airbag has a dual inflator system that matches the level of deployment to impact and passenger conditions. In general, a low impact will ignite one inflator and a high level of impact will ignite both inflators, which deploys the bags with a greater level of force. But before this happens, several sensors are involved to determine if the bags should be deployed at all.
There is a pair of weight sensors under the front passenger seat above each seat rail. Load placed upon the seat is converted into an electric signal by a strain gauge within the sensors, and this signal is sent to the seat weight sensor control module located below the seat cushion center, which calculates the weight based on the signals from each sensor. This information is then sent on to the SAS control module. If the weight upon the seat is less than 66 pounds, the passenger airbag simply will not deploy. Nor will the seat pretensioners or side airbags if the vehicle is so equipped. When the passenger seat sensors detect weight on the passenger seat that is greater than zero or less than 66 pounds, a Passenger Air Bag Off warning light will activate in the center console for six seconds after the ignition is engaged to inform you that the passenger side air bag is deactivated.
It doesn’t stop there. A sensor under the driver’s seat monitors its fore and aft position to determine if the driver is a safe distance from the steering wheel air bag. The sensor consists of a metal plate on the slide seat track that will slide through a groove in a fixed sensor if the seat is moved up to a position for the airbag to be deployed safely. When the metal plate is within the fixed sensor’s U-section, a circuit is complete and the SAS sensor knows that the driver’s side air bag should not be deployed.
In addition, the SAS control module monitors if the driver and front passenger seat belts are buckled. If not, (and the passenger seat is occupied) the threshold by which the air bag will deploy with greater force is lowered to attempt to compensate for the unrestrained body. If this sounds like a reason not to have to use your seat belt, it is not, as using your seat belts allows the air bags to operate in a more nuanced and balanced fashion.
And then there are two crash zone sensors: one in the very front of the car and another in front of the cabin. The system works like this: In the event of a frontal impact the two sensors use their relative positions to determine the impact’s angle and severity. This information goes to the SAS control module which already knows the driver position and the weight of the front passenger. The module processes all the information based on a set of mapped-in logic and then determines if the airbags should activate at all, and if so, how forcefully each bag should deploy.
When an air bag inflator is given the signal to deploy, the igniter builds up heat and ignites a combustion agent. This, in turn causes the combustion of a gas-generating agent which releases nitrogen gas. The nitrogen is cooled through a filter and then injected into the bag. The fabric of the bag is ventilated so that the bags quickly deflate after cushioning impact of the driver or passenger.
Sensors in the front passenger's seat determine the occupant's height and seating position. If the occupant is of small stature and leaning into the side air bag deployment path, these sensors will prevent the side air bag from deploying. Automatic seat-belt pretensioners are also standard on both front belts for added occupant protection.
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Also, does anyone know, what is the lowest height/weight recommended for the RX-8 front passenger seat? The standard "twelve years old" cut-off seems very imprecise to me.
Thanks.
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'04 Velocity Red Sport: "There's nothing to fear."
well if it did then i think the little circle next to the glove compartment would light up like in this photo from rotarynews.com. it was taken during their pre-prod drive at Laguna Seca. i believe it does this in other countries but have no proof.
Originally posted by zoom44 well if it did then i think the little circle next to the glove compartment would light up like in this photo from rotarynews.com. it was taken during their pre-prod drive at Laguna Seca. i believe it does this in other countries but have no proof.
My understanding is that in other countries Mazda provides a passenger airbag on/off switch - that picture is either the switch itself or the warning light for the switch.
As far as I know, the RX-8 does have sensing for the seat position and dual-stage airbags. There are technical papers and highlights around here somewhere that may cover this in detail.
Regards,
Gordon
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___________________________________ 2004 Ti Gray RX-8 - Canadian GT, 6 speed, no moonroof, delivered July 22, 2003 1996 Miata leather package, soon to be faster than the RX-8...
2002 Audi allroad wagon - 2.7 twin turbo, 6 speed manual trans
Haw. I think you're missing the point, Stew. The idea is it adjusts the airbag force based upon the passenger size, and doesn't deploy if no one's there. Good idea, IMHO.
Haw. I think you're missing the point, Stew. The idea is it adjusts the airbag force based upon the passenger size, and doesn't deploy if no one's there. Good idea, IMHO.
Wouldn't it be better to not have them at all? Seat belts, roll cages and helmets are better IMO... running into an airbag is like doing this ...
the manual airbag on/off switch is required by law in all 2 seat cars.
i personaly am not so sure about the sensors, if I have a crash I want the airbag to go off, I dont want the computer to decied the airbag might hurt me (law suit against mazda) and not go off.
Also, I dont think cars should start or run at all with out the all the people in the car wearing their seat belt....and I mean have it on, not just buckled in.
I called Mazda N/A Customer Service to check into this exact issue.
I have three daughters - ages 10, 8 and 2. A 4-seater car works for me, but only with certain considerations.
When I was car-shopping I test-drove a 2005 Mustang (8,000 miles, $17,000, exactly the 'winning blue' color I must have for all of my cars). I noticed the Passenger Airbag Off light was on when my oldest sat there (she's about 60 lbs). I liked the tough-looking new body style on the Mustang, but I really wanted the rotary power and the free-style doors.
At first I was looking at used 2004 RX-8s, but then I found a brand-new one down in Maryland. Anyway, I called Mazda to check into airbag safety.
According to Mazda Customer Serivice the U.S. spec 2004 RX-8s have no occupancy sensors at all and no controls to disable any of the airbag systems. Sensors will deploy particular combinations of the airbags based on the nature of the crash (see owner's manual).
Now (is this getting off topic or getting to the real issue at hand), this begs the question - what size person is safe in that front seat? I happen to have a 33-year-old friend who is only marginally taller and heavier than my 10-year-old so it would be foolish to simply say 'no one under 12 in the front seat'. I broadened my search beyond Madza and looked into US DOT, NHTSA, state DMVs and various other websites. I couldn't find hard numbers for height and weight for these 'tween' sized persons (please post a link if you find some). Infant carriers, toddler seats and booster seats are specified to the nth degree, but once a child is too big for a booster seat laws and regulations get vague.
I never found any evidence of a reported death of an PROPERLY SEAT-BELTED* under-sized passenger due to airbag impact. In fact, more than one report said exactly that. I've heard ancidotes of small children having head trauma or even blindness due to airbag impacts, but every case I can recall involved some idiot parent or grandparent indulging a tiny six-year-old who really should have been in the back and not even having them seat-belted.
My own judgement was that a front seat passenger must:
1) sit tall enough in the seat for the shoulder harness to fit,
2) have legs long enough to allow the knees to bend at the front of the seat,
3) sit far enough back from the airbag to prevent impact with either the opening dashboard or an accellerating airbag.
(this includes my 33-year-old friend too)
In addition to the other sources I mentioned I happened to meet the driver's airbag in a 1995 Pontiac Sunfire back on September 25th, 1997. I got a good look at the size of the passenger's airbag too (huge). I've given a fair amount of extra thought to airbags ever since.
This may be entirely off topic, but I was also researching the dimensions of the curtain and side airbags because I intended to install a toddler carseat in the back. Mazda's information satisfied me that the airbags would not strike the carseat itself.
I don't know what info you are looking for but I do know that the seatbelts in the RX8 have a sensor that sends information to the ABS system. So it knows when the passenger/driver uses thier seatbelt.
Thanks for a very informative and thoughtful post, Cool Blue. I think it was all directly on thread, for my purposes. (Too bad the RX-8's airbag system is not as avdanced the the Mazda3, in terms of sensors. )
BTW, my kids are 11, 8 and 6, and your research helps confirm that the younger two are too small for the front seat of my RX-8, if I'm to err on the side of caution as I should.
My 11-year-old daughter is 5' 2" tall with long legs, so she's as large as many adult women and I have no problem with her in the front seat.
Thanks for a very informative and thoughtful post, Cool Blue. I think it was all directly on thread, for my purposes. (Too bad the RX-8's airbag system is not as avdanced the the Mazda3, in terms of sensors. )
You're welcome. Since I'm on my 2nd life thanks to airbags I figure I'm obliged to help where I can.
I had the same thought about more advanced sensors after seeing them in the Mustang, but later I decided they wouldn't be much benfit anyway. I don't often have need to put an undersized person in the front seat and the lack of a sensor helps me resist temptation. The front airbag isn't the only reason to keep the little ones in the back (though it's likely the most compelling).
What's harder for me is remembering not to put an inappropriately sized package in the front seat.
So I installed Power Seats and have been getting Error Code C1981 Driver Side Seat track positon sensor circuit open. We messed around with the wires in order to get power to the seats and operate it. I'm thinking maybe we reconnected some wires wrong, back into the connector?
What the heck is goin on? Does that mean I missconected some of the wires? Where's the Sensor located, and where are the wires for it?
as for the sensors i think the newer models have em but the 04 and 05 model years didnt but im not 100% sure im usually the only one im my car and my gf so i dont really care coz the airbad deploying in case of an accident wouldnt hurt either of us ...
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2004 TiGrey AT, AEM CAI, Greddy SP2 exhaust, S-Techs, Metra Kit Eclipse head unit, blacked out emblems and taillights, LED interior lighting, footwell lights, led fogs, bride seat, rotorpros drilled slotted rotors, ebc redstuff pads, greddy rear strut bar, evo-r front lip, mazda speed side skirts, mazda speed front strut bar, TCSportline CF hood, AP dr midpipe,
I'm not sure what year the seats are out of, mine's an O5. I got the error once the seats are installed. If the 05's didnt have the Seat Track Pos sensor, how would the car be expecting a Value?
I'm trying to figure out if one of the wires is connected wrong, where the sensor is, if i can trick it or bypass it somehow...
I won't pass inspection here, with the airbag light on...
Yeah, but it was useful to see Cool Blue's post. Explains why he reacted badly in a different thread when I said that the '06s do have a passenger sensor and "air bag off" light. Never knew the ordeal he went through researching it for his earlier model. Really good guy... I miss his posts. Hope he's having a good time deer hunting.
Ken
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2006 MT, Galaxy Gray
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My 06 has a light next to the dash to indicate if the airbag is on or off. Today I had a 19" tire sitting on the passenger seat with no seat belt, the airbag light up
awhile ago i had a fairly small petite woman in my car and she had the seat wayy up for my friend in the back, and the light came on. Then again i don't recall wheather she was wearing a seat belt or not so maybe it was a combination of the two things... too close and no seat belt, or maybe just no seat belt turns it off... not really sure.
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