We bought a 2006 Hyundai Sonata in July 2005, just after the new model came out. Shortly after, I noticed something strange: About 50 percent of the time, the "airbag disabled" light would come on while I was driving the car with my wife in the passenger seat. My wife is certainly larger than our children, so the light should not have been triggered.
She took the car back for warranty service. The dealer checked out the car and said it couldn't do anything about it. We repeated this a number of times. As an EE working in the automotive industry, I got fed up with this lackadaisical response to a critical safety issue. I downloaded a copy of the FMVSS (Federal Motor Vehicle Safety Standard) that applied to airbags and seats (all 500-plus pages), and I waded through it to find exactly what the requirements for this "safety" feature were.
The intent of the requirement wasn’t stated anywhere in the document. Nor could I find "real" specifications. The only item I found was a test procedure for verifying compliance with the unspecified requirement. It involved a couple of sandbags -- one the weight of the "average" child, the other 150 pounds, which supposedly represented a small adult. The test called for setting the front passenger seat's fore-aft range to its center and setting the seat back angle to midrange. If the "child" sandbag is on the seat, the airbag should indicate it is disabled. If the "adult" one is on the seat, the airbag should be enabled -- and thus no light.
Apparently, the Hyundai engineers designed to the test, setting the seat micro parameters to a very small range determined by the seat position specified in the test. Only then would the airbag be enabled.
It gets better. The National Highway Traffic Safety Administration ordered a full recall campaign from Hyundai. We received the notice and brought the car in. The service manager explained that we would have to leave the car for several days. The dealer needed to remove the passenger seat assembly and ship it to a service depot in California, where the entire seat computer assembly would be replaced. It actually had no way to reflash the micro other than through the OBDII (onboard diagnostic system) port!
Now that the seat has been repaired, the airbag-is-disabled indicator only comes on about 20 percent of the time.
This entry was submitted by Mark Rackin and edited by Rob Spiegel.
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The best solution would be for airbags to be optional equipment, not a very expensive stack of ordinance forced on everybody. BUT safety DOES NOT SELL! This has been demonstarted repeatedly over the years. The only way to make safety profitable is to bribe congress into forcing everybody to buy it. This is not a new discovery, it was demonstrated in the auto industry many years ago with anti-lock brakes. When they were an option, they were an expensive money-loser, but once they became nandatory, they are a profit source.
With the front passenger airbag there was a very real probability of the back firing in a collision with nobody in the seat, thus adding about $2000 to the repair costs of a collision. Even worse, having a frail old person or five-year old in the passenger seat did repeatedly result in the passengers death by this inescapable option. Thus came the seat switch. In my car the passenger airbad disabled warning comes on with books or a briefcase on the seat, which is fine, since they certainly don't need any protection to survive.
The fact that the specification is not clear about exactly when it must disable and enable shows that the rule was not created by engineers, or anybody else who knew what they were doing. Perhaps they were monkeys?
I have a similar airbag situation in my two Suzukis. If I go somewhere alone, the light says PASSENGER AIRBAG OFF. For example, if my girlfriend gets into the car and I leave without turning the ignition off and restarting the car, the light remains on. Normally, I stop, get out, escort her to the car, and restart, so this issue may have been present all along and I never noticed it until now. (She's not a small girl, so I don't think it's a weight / sensitivity issue.) Since both of my Forenzas, an '05 and an '04 act exactly the same way, I suspect it is inherent in the design of the system.
I agree with OlderEngineer. I kept all three of my kids in the backseat until they were nearly adults. A simply look at statistics will scare you into this behavior. Thus, sensors in the passenger seat were never an issue. I can't see the idea of putting a kid in the most dangerous seat and then figuring out how to make it just a tad safer.
Measuring the weight/presence/size of an occupant directly is not a simple matter, as a passenger's feet may rest on the floor pan, making the passenger seem lighter. Cinching a seat belt on a child seat may add to the load on the cushon, making the occupant appear heavier.
Most of the occupant sensing systems I am aware of (I was involved in the development of one of these systems before I retired) use some sort of mat embedded in the foam of the seat. Most of the error in the system is involved in the placement of the sensing technology (membrane switches, capaitance elements, etc) to optimize the estimate of the passenger weight. The closer the sensing mat is to the top surface of the seat, the better weight estimate can be made. However, this position makes the sensing mat much more vulnerable to damage.
Well designed software can only estimate occupant size based on the "goodness" of the sensor data it sees. If the sensing mat is the culprit in the initial complaint, no amount of software upgrades will ever cure the problem.
It is easy to pass the test defined in the FMVSS standard. However, designing a system that is effective in the real world is much more complicated. "Due dilligence" required that we use a veritible Kama Sutra of occupant positions to extend the sensor capability beyond the test requirements to encompass real world usage.
Sounds like the mercury switch in the seat isn't oriented correctly. I would imagine they have to be sent off to a repair facility because of the liability issues. The airbag module under or in the seat has it's own power source and can be triggered even when it's disconnected from the rest of the car if not handled correctly.
The triangle exclamation mark symbol on the dash is correct, something on your car is going to be permently damaged. probably resulting in failure if not looked at. If it were real serious, would have died right there.
Personally, I wouldn't buy a car with navigation builtin. Hand held units do just as well and far cheaper. But gadgets sell cars and can part people with even more money.
Isn't the lesson in all this to buckle the kids in the back seat (using a car seat when needed) and always where your seat belt and shoulder harness?
Cars are no longer just a means of transportation but mobile communications and entertainment capsules. The public brought this on themselves by demanding more and more features to take their mind off the task of driving and then expecting the government to protect them from the inevitable injuries which occur by not paying attention.
When I see car ads that only speak up how "connected" I can be, I automatically remove them from my want list. If the manufacturer doesn't first try to convince me that it's a better car I don't want it!
I don't know what planet you live on! ALL manufacturers have had issues similar to this; just because you never got a recall notice doesn't mean there isn't a problem. Try Googling "airbag + auto +recall" to open your eyes. Just in the past month, Ford recalled 1.5 MILLION F150s for an airbag problem (this one was possible unintended triggering, even more dangerous); GM recalled 50K Cadillac SRX models for another. Also Toyota, etc. There are a couple of web services (free) that will periodically e-mail you notices of recalls, service bulletins, and common complaints for specific models and years. I used one of these until very recently for both the 2006 Sonata and my 2003 Camry (whose biggest problem I had was a bad steering column that Toyota refused to repair/replace under warranty). I finally unsubscribed because there were so many of the same issues every month reported by new victims it was very discouraging.
Its one thing if they decided that the firmware won't be changed (yeah, right) and they wanted to leave that feature out. However, what sort of design is it that the dealer can't even change the controller out...and on a recall claim, no less?
If this were just a guv'ment problem (really a lawyer problem), then why haven't we heard about a rash of these problems with other auto manufacturer's products? My Freestyle has a similar feature and it seems to be working perfectly.
As usual, it's worse than that: the regulations include a specific intent that weight alone is NOT sufficient, since apparently they believe height is also an issue. That's the reason there is even a mention of fore/aft seat position; the theory is that if the seat is too close to the airbag location, it can do more damage to the passenger than the crash would! I believe that latest technologies for airbags include variable inflation force to give options other that activate/deactivate. You're absolutely right about the automakers responding rationally to an irrational situation.
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