R Brantley

My wife uses a 1 1/2 inch foam filled seat cushion (14 x 14 inches) when she rides in the front seat passenger side of my 2018 Q7 Prestige with the Luxury Package. She buckles in the seat belt but the car does not detect her and does not turn on the passenger side air bag. We can drive for 10 minutes to over an hour before it recognizes her, omits a bing noise, gives me a message on the dash board, snugs the seat belt, and the light overhead changes from Passenger Airbag Off to On. My wife is 5 ft 4 and is not big by any stretch of the imagination she's had back problems and needs the cushion for comfort.

I've taken the car back to the dealer 3 times, the first time was no trouble found, second time they replaced the overhead lamp module but that didn't fix anything. The third time they put a computer in the car and watched what it did when she sat on the pillow. The car, or seat, or something, thinks she's a child car seat and therefore won't turn on the airbag. The dealer said that appears to be normal and the cushion is confusing the seat so their recommendation is to change pillows or just put up with it. They said that even though the airbag is set to off it will still deploy it will just be delayed by a few microseconds. We did change to a pillow similar to a neck pillow but it didn't make any difference.

This seems like a safety issue to me, has anyone else run across this? I can keep taking it back and raising cane about it but I don't see them doing anything.

hayde_bre

Is it possible seat cushion is not applying pressure where the car expects a normal person would apply, therefore assumes you have bags/child seat/etc there and disables the airbag? It could be confusing the sensors like dealer said. How is the behavior with other Q7s in the lot, or other cars like Q5?
Have you tried adjusting the seat back/angle/etc to see if that helps.
This is really interesting. The sensors use combination of seat bottom and back (to tell if it's a person or not) sensors so if your wife is sitting back, with seat belt buckled, it should detect it as real person and enable airbag. It's scary, and I never heard airbag still deploying when you have the light saying "Air Bag Off" lit.

AMDG75

We noted the same thing in my A6 when my wife used a long cushion for 3+ hour drives. Was informed that the sensors in the Audi, as well as other makes, are not based on weight/pressure but rather capacitance - essentially the ability to hold a charge. I did not sleep an a Holiday Inn Express, so really cannot explain well other than to point out that the cushion acts as an insulator. I haven't tried to see if one could "override it" so that the airbag is always on. Maybe someone else on the forum knows more about this.

You could use the opportunity to tell your wife that she does not weigh enough.

SYMAWD

How much does she weigh? Under a certain weight it will recognize her, but not activate the airbag.

R Brantley

My wife weighs around 125 lbs, she did tell the shop foreman that she wasn't going to put on weight just to remedy the problem. She's tried different positions in the seat including bouncing up and down which sometimes works. She can remove the cushion and is recognized but sometimes when she puts the cushion back it goes off again.

What everyone here has said so far matches what they determined to be the problem although none of them had heard of this before.

I do plan on going back to the dealer soon and have my wife try this in other cars there.

gsobol

The cushion is spreading her weight across larger surface area therefore reducing the reading on the pressure/weight sensor. It must be on the cusp of the threshold, that's why it sometimes registers and sometimes it does not. Test it yourself by sitting on the cushion and see if and when will the car recognize you in the seat. Is the reaction delayed as the cushion deforms? I would be careful with the claims regarding airbag deployment when the light is out. I believe, the airbag will not deploy under these conditions.

mcdream

I don't have this issue but my car (EU model) turns on Passenger airbag every time I start the car (bing! Passenger airbag ON). If anyone gets in or out it doesn't show me any more messages. So based on your problem there might be a setting somewhere (using VCDS or ODB11 cable) that can be changed. Not sure if dealership will do that.

AUDI1880

This idea is way out there, but maybe if you placed something firmer, like a hardcover book between the seat and the cushion your wife uses, it may press harder against the sensor in the seat, and then register her presence?

AlbertQ7

I like the idea of having you sit in the seat with the seat cushion. Earlier, someone suggested capacitance as part of the mechanism, in which case even your heavier weight may not trigger it. If true, you could wrap the seat with foil to make it conductive? 😜
If it does trigger with you in the seat, than it is more of a weight and weight distribution issue and perhaps the stiff book between the cushion and seat will help.

stevenpoint

If it is capacitance maybe something like aluminum foil under the cushion or something