This has to be one of the strangest car issues I've seen.

I've been having a minor issue with my company car, a 2015 Chevy Malibu. For the last month or so, I'd get a random warning chime. Same chime as the parking break on, seatbelt warning, low fuel, etc.. Except I couldn't find anything wrong, and the screen on the dash didn't display the expected issue. It was seemingly random, just a couple chimes here and there. I took the car in for an oil change at the Chevy dealer, and mentioned the issue. They couldn't duplicate or find a fault. 

I figured it out out while sitting in my living room. I had set my iPhone down on my laptop, which I had noticed makes the touchpad act funny. It popped in my head that I had switched phones a couple months ago, right around the time I started getting the chime in the Malibu. I went out to the car to test my hypothesis. 

You see, my new phone doesn't fit neatly in the cup holder like the old one did. There are phone slots in the console, but they barely hold it and it falls out easily, so I often set it on the passenger seat. 

I get in the car and start it up. I remember that there are passenger side airbag and passenger seatbelt warning lights, but they don't display on the dash- their indicator lights are up on the headliner above the rearview mirror. I don't often look at the ceiling when I drive, so I didn't notice them. I set my phone on the passenger seat. Sure enough, the "passenger airbag on" and "passenger seatbelt" lights illuminate, and the chime rings. I repeatedly pick up the phone and set it back down, and the lights respond to my actions. 

So what is going on here? How is my phone triggering the sensor in the seat? I thought is was supposed to detect weight?

I haven't found any links worth linking, but it sounds like seat occupancy sensors are getting more "clever" in an attempt to differentiate adults from kids from car seats from paperweights... And while a lot of it seems to be weight, there's certainly been some other funky stuff (trying to remember whether the mention of heartbeat detection was more than experimental in one of the things I found).

Do you happen to have a stack of playing cards or something about the size and weight of your phone but lacking any electronics/metal? See whether that elicits the same response? I don't know what, if any, additional sensors the Malibu has, just trying to think how to see what it's sensing... Short of actually, you know, Googling for '15 Malibu occupancy sensing...

I've had airbag sensors that will detect things about the weight of a phone. I can't remember what car, Mazda2 maybe? I couldn't put ANYTHING on the seat or it would trigger the light. My phone would do it. Shopping bag with a single item. Kids lunch. 

Boost_Crazy said:I figured it out out while sitting in my living room. I had set my iPhone down on my laptop, which I had noticed makes the touchpad act funny.

So what is going on here? How is my phone triggering the sensor in the seat? I thought is was supposed to detect weight?

It shouldn't, but then your touchpad shouldn't act funny either.  The common element is the phone.

The computer speakers I used for years would buzz annoyingly exclusively when an ATT cell phone was about to ring. Maybe all the spying on you doodads in the iPhone are interfering with the cars computer?

In reply to Ransom :

I am aware of efforts to have ECG sensing capability in car seats. Was playing around with the technology for a different purpose, but the stuff is out there. Not yet mainstream that I am aware of.

Glad my car is from the beginning of the last decade. This stuff is getting out of hand. My car apparently doesn't even care if you put a seatbelt on or not.

freetors said:

Glad my car is from the beginning of the last decade. This stuff is getting out of hand. My car apparently doesn't even care if you put a seatbelt on or not.

Yet another example showing why I started the “Who makes the most rudimentary cars?” thread recently!

Borrowed a 2010 F-150 for a long towing road trip a few months ago and it loved to complain about PLEASE REMOVE LOOSE OBJECTS NEAR PASSENGER FEET if the phone charging cable wandered too far over from the center console.

that's almost as weird as my issue in the Abarth. Going into work I go over a drawbridge. Right next to it is an antenna farm for a couple of Radio Stations. EVERY time I go across the metal deck of that particular bridge (other bridges do not do this) it kicks the radio off of USB and onto proper radio.

freetors said:

Glad my car is from the beginning of the last decade. This stuff is getting out of hand. My car apparently doesn't even care if you put a seatbelt on or not.

Except that if you are in an accident, and do not turn the airbag off by hand, and you have a kid in the passenger seat, you may set off the airbag when it does a lot more harm then good.  The point of the sensor is to make sure that the airbag does not go off when someone is so light that it would harm more than help.

For me, it's not a big deal- since we don't have kids that will ever drive around in my Miata.  But I would not dismiss the technology out of hand.  Heck, I'd appreciate a rear camera even in my Miata- as my neighbor kids do leave things in the driveway we share that could be missed.

Looking around as you get in the car is a big help.

I think fellow GRM'er imgon had this issue with his 04 or so GMC Yukon XL. It wasn't a phone but rather his metal clipboard that was just heavy enough to trip the seat occupancy sensor or whatever you call it. I seem to remember him chasing troubles with the airbag light/sensor for a while only to find it was the clipboard.

mazdeuce - Seth said:

I've had airbag sensors that will detect things about the weight of a phone. I can't remember what car, Mazda2 maybe? I couldn't put ANYTHING on the seat or it would trigger the light. My phone would do it. Shopping bag with a single item. Kids lunch. 

If enough farts build up in there the air bag is always going to be on

The FR-S does this. I can have about 30 lbs of backpack on the passenger seat, FR-S don't care. Nothing on the seat and drop a cell phone on it, the seat belt warning chime goes completely bonkers. 

I makes me question how much radiation these things are putting out, and that I might be nuking my nads with it in my pocket.

RevRico said:

The computer speakers I used for years would buzz annoyingly exclusively when an ATT cell phone was about to ring. Maybe all the spying on you doodads in the iPhone are interfering with the cars computer?

Yes! My Dell speaker bar lets me know I'm about to get texts. If it buzzes for a couple seconds I'm getting pictures attached

I guessed it in the first paragraph. The first time the caddy did it, it freaked me out. I get the safety thing...what I don’t get is why the car has to remind me every 5 minutes on a 40 minute ride that my berkeleying phone and a carton of smokes are on the seat. AFAIK, there’s no way to manually make STFU short of rifling through the crap on the seat and moving it all to the floor/back seat while cruising at 75mph...which is, of course, totally safe.

Like Clarkson said of the V: “It BONGS”

Given the phone being a phone, and the laptop having a touchpad, I am going to guess that the occupant classification system works partially on detecting capacitance and that is why the phone is particularly affecting it. 

I googled the thing, i just didn't read much of it.

Does buckling up the appropriate seat belt stop the chiming? Seams like an easy enough remedy to allow you to put stuff where you want it and keep your sanity.

It’s the same reason they’ll throw you out of a power plant if they see you with a cell phone around the control equipment and the panel doors are open.

RedGT said:

Borrowed a 2010 F-150 for a long towing road trip a few months ago and it loved to complain about PLEASE REMOVE LOOSE OBJECTS NEAR PASSENGER FEET if the phone charging cable wandered too far over from the center console.

This reminds me of my now-scrapped washing machine that was having problems.  I pulled the error codes on it (ugh, the fact I can do that is the main problem) and one of the codes was "too many suds."  Another was "user depressed control for more than 10 seconds."  Thanks.  How exactly is this helping me?  

I replaced it with a circa-2000 used Kenmore with all mechanical controls and harvested the motor, drain pump, etc from the far-newer machine. 

My wife’s Fiat was very sensitive to anything on the front seat. I got an extra seat belt end off eBay to plug in so it thought the belt was latched. 

Huh. Never thought about the latch thing. I actually have one for when my idiot brother who typically refuses to use a seatbelt rides with me.