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Airbag "off" warning light comes on when passenger uses personal cushion

14K views 27 replies 12 participants last post by  tex2670  
#1 · (Edited)
My wife uses a personal cushion when we travel. It has presented no problems when we are in our 2017 Tucson Limited (see special edit - next paragraph). But, her seat cushion, required for her comfort over a long period of time (due to little "posterior padding") has created quite a problem in our new 2022 Santa Fe Calligraphy. It is no problem when she drives. But when I drive and she is the passenger up front with me, even at 130 pounds, the light goes on warning that her air bag has been turned off. I learned in another forum that using a sheet of aluminum foil beneath the cushion would take care of the issue. We tried and it works, or, at least the warning light no longer comes on.

SPECIAL EDIT: On 4-11-2022, three days after making this original entry, my wife and I made an alarming discovery. As stated in the paragraph above we have been under the impression that this problem had not been an issue with our 2017 Tucson Limited. However, this evening after we tested the RDIF fabric one more time on our 2022 Santa Fe, we stepped over to the Tucson to check it out more thoroughly. Much to my dismay, we discovered that it actually has been an issue and that apparently we never noticed the "air bag off" warning light! Though this surely makes me look stupid or at the least, very weak in my powers of observation - it appears that in many of the over 80,000 miles we have put on that Tucson my wife as a passenger using a special personal cushion had no airbag protection. Duhhhhh. I don't mind looking stupid if it helps someone. When we placed the special fabric beneath her cushion, the air bag off warning light no longer displayed. At this moment we are feeling extraordinarily fortunate that we had no accidents. END SPECIAL EDIT.

From another forum a suggestion was made to use an RFID blocking fabric (I think they are called Faraday shields) and I have ordered that from Amazon. I expect that method to work too and to be more reliable and quieter than the thick aluminum foil.

But here is my question which reflects both my fear and my ignorance about how the ODS (occupant detection system) works: I am afraid that though both the foil and the blocking fabric do indeed cause the warning light to no longer appear - the air bag might still be inactivated and that we are therefore getting an incorrect impression that all is well. How would we know for sure - short of an accident? Would an on-board diagnostic II (OBDII) monitor be useful to verify that she is protected when the "airbag warning light off" indicator is not on due to our actions to override it? Or Am I needlessly worrying about something that is clear to you but foggy to me? I will appreciate any input you are willing to provide. I sure don't want my wife to have to ride in the back seat when I'm driving! She's my sweetheart for life.
 
#2 ·
I'm following this as well. My wife had back surgery and also has to use a cushion. Let us know what ends up working.

Not sure why the foil would work or not.
 
#6 ·
I'm following this as well. My wife had back surgery and also has to use a cushion. Let us know what ends up working.

Not sure why the foil would work or not.
Hello Bookworm,

I will be letting you know whether or not the Faraday fabric does the trick in the same manner as the thick aluminum foil. My wife and I will be testing it tomorrow so look for another message from me soon. I will have to then go one step further for peace of mind and do a diagnostic to see that the passenger air bag will be ready to function. I'll have to get my hands on a on-board diagnostic II (OBDII) monitor - assuming that will tell me if the airbag is not truly at the "on" setting. In any event, I'll let you know if I learn anything new.
 
#9 ·
From what I can gather the newer models use a new type of Occupant Detection System called Electrostatic Capacitance Sensor ODS. This system does not use weight to determine whether to turn the Occupant Detection System on and off. I don't pretend to understand it but the aluminum foil beneath my wife's personal cushion (which she must use for anatomical reasons dealing with pain) prevents the airbag off warning light from illuminating. This evening we tested one thin layer of copper infused EMF shielding fabric that I purchased through Amazon. It works also. Everything I've read tells me that if the warning light is off - the air bags are ready if needed. Still - I wonder.
 
#4 ·

Found this interesting video that shows how the sensor is implemented in Teslas.

If I were you, I would contact Hyundai consumer affairs so that corporate can coordinate with engineers and the dealer to give you information on what the weight threshold is and investigate whether or not you have a faulty sensor or programming updates need to be made to adjust the behavior (potential safety recall?)....This would give a lot more peace of mind than trying to trick or override the system.
 
#7 ·
Thanks, I appreciate it. With her back surgery, she can't use a thinner cushion and even has it with a hand strap as she has to bring it into restaurants, movies, etc. But at least with it she is comfortable.
 
#10 ·
Hey Mr. Bookworm! The EMF shielding fabric that I purchased through Amazon works. When the fabric is placed over the seat bottom and then my wife's personal cushion on top of the fabric, the "air bag off" warning light does not come on. Everything I've read so far tells me that when the warning light is off and the engine is running, the passenger side air bag should work if needed. But - I'm still concerned partly because I don't understand how the seat sensor works. I have been told that it does NOT directly measure weight. What I need is for someone who understands the system to let me know whether we are doing the right thing by using the Faraday shield method.

My wife's cushion has a few zippers which would allow me to get inside its cover. I'm tempted to cut the shield fabric to the correct shape so that it will fit inside. However the cushion has two strategically placed holes in it and I think that might cancel out the shield's effectiveness.

Please, will you and your wife test your vehicle passenger seat to see if aluminum foil works for you as it did us. The results will let me know whether or not I have some sort of anomaly in my 2022 Santa Fe.

By the way, the service center people where I bought the vehicle tell me that there is no way around our problem. That was during a phone conversation. In fact, the salesperson who sold us the Santa Fe which has less than 2000 miles on it) suggested we sell it (and get more money than we paid for it) and then buy a Palisade or a Genesis! That sounds crazy to me. Wouldn't the Palisade and Genesis have the same type of air bag warning system and we would therefore have the same problem. I feel almost alone with this problem. Thanks for helping.
 
#20 ·
These forums are great.
Been using seat cushions on both front seats since we got the 2021 limited Santa Fe, (The leather seats are just not that plush). I ran across this thread a year later, and never realized the passenger seat air bag off warning light was on. Today, did the foil test and behold the warning is now off. The seat cushion we use for that side is in kind of a pouch so the foil can be stuffed inside the cover and makes no noise. Kinda weird, but whatever works.
 
#22 ·
Hello KC! Thanks for the input. When I just re-read this thread it seemed to me that I wrote way too much on this subject - lots of repetition. I'm responding to make sure you know that I'm not an expert on this subject and am still learning. I'm uneasy about the method because though it causes the warning light to be off, I'm not certain that the air bag is active. I'd like to know some way to test that other than an accident or deployment of the airbag in any other way (I guess that all goes without saying). I'm hoping for more reassurance.

Back on April 10, 2022 TAGSF19U wrote:
"It would stand to reason that the warning light is only OFF because an occupant has been detected when the cushion is used with the foil or fabric. Therefore the airbag is active. Also consider that the light is off when no cushion is used and there doesn’t appear to be any concern for the airbag. Glad the foil and fabric help with this particular issue."

Of course that was encouraging. But please know that I'm not recommending this method to anyone until I learn for certain that it is actually valid.

elp_jc
provided much appreciated input on May 14, 2022. It sounds as though he's done some research. Please read both. I think these guys know what they are talking about.
 
#21 · (Edited)
I didn't know this, so learned something new today :). Has anybody found a small piece to fit just one seat? If yes, please post a link. Also intrigued what Hyundai used for a sensor on this car, and how exactly it works. But one thing is clear: If airbag off light in on, passenger airbags wouldn't work. If off, they'd work. It's basically like a switch, and anything wrong with it, would trigger a dash fault.
And yes, just like the Tesla video, OD sensors used to be the relatively simple pressure kind (Tesla uses a sensor on the driver's seat due to not having 'ACC' or 'IGNITION ON' switch). And I remember reading they should activate with about 60 lbs.
At any rate, the 'airbag off' symbol is pretty subtle, plus most of us are subconsciously used to it when driving alone, so it's perfectly normal not to notice anything wrong if you're not consciously checking it... which most of us will do from now on, if needed :). My wife hasn't used any cushions for the seats, but she's ready to on long trips, due to aging issues (sciatic nerve). Glad to find out about this. Thank you for posting it.
 
#23 ·
Thanks so much for this input. I'm not sure why I missed it when you posted it as I've just viewed it for the first time today, 6-6-22. It sounds to me as though you've done some research. You indicated that if air bag light is off - the airbag will work. Are you confident about that? Up until a few days ago I've been of the mindset that I would not be fully comfortable with this method until someone from Hyundai who should know informs me that it's valid. But - a few days ago I took my Santa Fe in for its first oil change, filter, rotation, and inspection and left with the impression that Hyundai dealership employees who should know their products very well certainly may not. They were unbelievably busy, rushing, and apparently understaffed too. I was frustrated enough that I never got around to discussing the airbag question with them. However, weeks ago, on the phone, they had told me that there is no way around the cushion problem. The jury is still out on their competence or level of knowledge. I have some more legwork to do now on an oil issue which will come up in the Santa Fe forum soon (unless it already has - at which time I'll throw in my two cents worth). On that forum my identity is "SeaBee Son." Once again - your participation is much appreciated.
 
#24 ·
If the 'airbag off' light is not lighted, airbags are active, period. There's nothing to second-guess. There would be a fault light if that was the case. The more valid concern would be if a light child is seated, leaving that RFID cloth by accident would switch the system on, when it shouldn't be on... and I'm afraid that'd be the case. But there's zero doubt what when light is off, airbags would fire up. Having said that, I still want to know what kind of sensor system Hyundai used, mostly out of curiosity.
 
#25 ·
Just thinking logically about this; The concern here is that even with the airbag warning light off (while using the Faraday fabric), the airbag system is still not enabled. This would imply that the warning light and the actual airbag system use different seat occupancy detection logic, or that the airbag system uses some supplemental detection system (above and beyond what the warning light uses). Beyond the fact that this makes no sense from a simple design standpoint, I would think government regulations would require the warning light and actual system to be tied together and always "in sync". Otherwise, the warning light is pointless. Anyway, just my thoughts on this.