Passenger airbag works 50%

It seems like if the customer has complained multiple times of the airbag not working (which is a huge safety and legal issue), all avenues should be utilized. If that means tearing out everything that has to do with the airbag and replacing it all, then do it. If there is a sensor that can be calibrated, that should be the first thing done. From what I understand, they get paid by Toyota to handle repair issues under warranty. If that's the case, they should get to work and fix the problem.

 

No offsense, but a computer problem isn't exactly life threatening. I can understand your point for many other things, like a noise in the engine bay or something like that. But an airbag is very crucial and integral to the crash design of the car. There should be a separate consideration for safety items, and the dealer should at least inspect the components like the harness and seat switch. As well as try a calibration.

 

I wouldn't consider this issue exactly life-threatening, either, any more than driving itself is inherently life-threatening. The failure of an airbag alone does not directly threaten your life like, say, the failure of your brakes. You'd also need to be in a collision serious enough that the airbag would protect you, but not serious enough that the airbag wouldn't be enough to save you. You'd also have to have a passenger in the car, which for most people, isn't all that common. (And, for that matter, there are plenty of computer problems that ARE life-threatening - like computers used in life support, nuclear plants, or air traffic control; or if your car's computer decided to set off the airbag for no good reason. )

That said, I'm not saying it's an excuse for the dealer to not look, or to not try to fix it, nor is it an excuse to not perform a calibration. It also might be reasonable for him to take a guess at the likely culprit and replace one part (e.g. the seat sensors). But I think it is not reasonable for him to start tearing apart your car and replacing every single part of the system. Just doing that might make the problem worse (i.e. the airbag might never work), or could create a different problem - and he couldn't even tell if he had fixed the original problem.

So go to the dealer and be insistent that he take a look and perform whatever calibration is specified. Be polite but firm, and keep your expectations reasonable, and hopefully the dealer will recognize that and try to meet your expectations.

 

All of those "life critical" computers you mention have safety protocols and redundant backup systems in place in case of a failure. Life support at the very least has a backup beeper which alerts the nurses of a failure. And for any of those mentioned, if an intermittent glitch appeared, they will send someone out to check it , run diagnostics, and replace any suspect parts. They don't play around with any of those systems. They don't do the whole, well if it doesn't happen in front of me, then it didn't really happen deal. They do everything reasonable, to see if they can isolate or resolve the problem.

Airbags are integral in the design of the crash safety system in automobiles. That's why GM is recalling almost 2 million cars as of now because in some of the crashes caused by the ignition switches, the airbags also didn't deploy because they had no power. Some of those people would still be alive today.

 

I dated a girl that was about 100lbs soaking wet. That was in my 2008 impreza, the airbag was designed for 105lbs i believe, and while she was sitting in the passenger seat, the light would turn on and off throughout our driving. She was right on the limit of the switch, and moving about in the seat would cause it.

 

The repair manual lists the classifications:
NG (No Good)
Off (Vacant)
CHILD (<36 kg/79.37 lb)
AF05 (Adult Female, 5th percentile; 36-54 kg/79.37-119.05 lb)
AM50 (Adult Male, 50th percentile; >54 kg/119.05 lb)
FAIL (Failure detected)

When vacant, the lights are off, and the airbag and seatbelt pretensioner are disabled. When a child is detected, the Airbag Off light is on, the airbag is off, and the pretensioner is enabled. When an adult is detected, the Airbag On light is on, as is the airbag and pretensioner. The airbag can deploy with two strengths, depending on whether it classifies you in the "small adult female" or the "average adult male" category. The side and curtain airbags are always enabled. It's worth noting that those weights are for the amount of weight on the seat, not for the weight of the passenger - e.g. to test the system, they're supposed to put a 30 kg weight on the seat, and check that the car reports it as 30±3.2 kg. So essentially, half the weight of your legs doesn't count. (Thanks to xkcd's @whatifnumbers recent tweet, I know that an average human leg supposedly weighs 22.1 kg/48.73 lb; obviously, this is the same weight as half of 2 legs. And 119.05 (measured seat weight) + 48.73 (unmeasured leg weight) = 167.78 lb, which is pretty close to the NHTSA's specified 50th percentile male weight of 172.3 lb.)

In general, it's a GOOD thing if the airbag is disabled for your 99 lb passenger; the airbag is designed to be safe down to the 5th percentile adult female, who weighs 108 lbs (about 80 pounds of which are on the seat). Below that weight, the airbag may deploy with too much force for your lightweight passenger, and poses a threat to them. For lightweight passengers, the seatbelt is usually sufficient to restrain them; with less body dragging on the seatbelt, it will probably decelerate them before the seatbelt and seat deform enough that they hit the dash, so the airbag isn't needed. If it deploys anyway, it has so much momentum that it could cause injury. (Momentum is mass times velocity, so an adult moving towards the dash has much more momentum to cancel than a child does - imparting that much momentum to a child could cause them to move *backwards*.)

All that said; there is a calibration in the repair manual to set the zero point of the occupant classification system. After that is performed, the dealer should perform a sensitivity check by placing a 30 kg solid metal weight in the seat. If it doesn't measure within the specified range, the manual prescribes first tightening the seat bolts, and then replacing the front seat cushion spring assembly. (Most likely, they might want to start with the sensitivity check, to see if the zero point calibration is even needed.)