2006 Z4: Airbag warning light on because of passenger seat occupancy sensor failure

[dadlad]

Repair cost is very high - first two estimates are $1200 and $1600. Safety is not an issue at this point as the passenger airbag WILL deploy whether or not the seat is occupied. The only issue then would be if a small child were an occupant, but that will not occur. I am the sole occupant 99% of the time, and the only passenger is my wife. So at this point I am considering a bypass or emulator which would signal to the system that an adult is in the seat. The warning light could then be turned off and would remain off, with the airbag still fully deployable.
I have found several sources on EBay; many from UK and Germany. Has anyone had experience with this particular problem and with an emulator? Are there other workarounds? Would appreciate any suggestions or advice, positive or negative.

[montaillou]

Is the problem with the sensor only? Because I think it'd just be cheaper to replace the entire seat. Or to strip the sensor from a used seat and to replace it.

[dadlad]

Is the problem with the sensor only? Because I think it'd just be cheaper to replace the entire seat. Or to strip the sensor from a used seat and to replace it.

The sensor is integral to the bottom seat unit, per our BMW dealer and local foreign car repair shop, so the seat bottom itself, which runs $800 or more, is required as a replacement. An emulator, at $50 or less, seems to me to be to be a workaround solution, although not optimum.

[Steve Jarvis]

FYI I checked on the needed sensor/pad for my 2001 M3 and the cost of the part from Turner Motorsports was just under $170. See image below.

Later, Steve
Airbag Switch.JPG

[dadlad]

BMW provides the sensor for a 2006 Z4 only as an integral part of the bottom seat unit at a cost of $800 +. (You get the entire seat unit together with all the wiring and connectors). I've see online offers of the mat only for less than $200, but am not confident in some of the sources, nor that that I could successfully tear apart my vinyl-upholstered seat and do the whole job. I could certainly be wrong at this point, and would welcome some assurance or advice about this particular 2006 Z4 seat/ sensor mat. Thanks for the reply.

[Bill837]

Wouldnt the first step be to ensure the electrical connection is good before assuming the expensive part is bad?

[montaillou]

If it's integral to the seat and you're not in a particular hurry you could shop around for people parting out their cars or look at a salvage yard. Yards typically charge half retail or less for parts. Now this might necessitate you having to do the work, but some independent mechanics will install with parts provided, but without any sort of warranty.

[Buddyell]

Just did mine a month ago. $1200. at the dealership, mat and sensor were replaced. The advantage is a 2 year warranty on the part. I'd hate to go thru all that work and expense and have it fail in a year.

[dadlad]

All connections are unfortunately physically solid.

[jabramson]

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I don't know if all my complaining the NHSTA and BMW, but I recieved a letter yesterday that the occupancy mat is now having extended warranty on it for 15 years. Brought it to the dealership to get it finally fixed. If you had this repaired and paid for this, you may want to go to the BMW site about this. I'll attach copies of my letter.

Here's one question though. They are trying to tell me I need the seat belt replaced because it's also throwing a code. I've read in places that disconnecting the seat harness and the occupancy mat going bad can throw this code and will reset when the occupancy sensor is bad. They want over $300 to replace the seat belt sensor. What do I do? Will it reset after the mat is replaced. They're telling me the seat belt sensor has nothing to do with this and won't stop the display on the dashboard of the error. Meanwhile, the seat belt doesn't give an alert when not fastened at all. But is that because of the occupancy sensor being bad? Worst would be if I have the seat belt replaced later it would cost about $100 more at the dealership. I'm inclined to not have the dealership replace the seat belt sensor.

I'd appreciate any thoughts on this seat belt sensor issue.

[Buddyell]

Just a follow-up. I received the same letter, and have sent the info requested to BMW. I will let you know if and when I get the rebate check for $1200.

[Marcoose]

It must be the season. The airbag warning light is on, and the unbuckled passenger seat belt warning light isn't coming on. Aargh. At least the guy I go do, Dave at Ottowerks here in San Fran, is old school and crafty on finding inexpensive alternatives. I'll post an update soon. (Oh, mine is an '03.)

[Marcoose]

Quick update. Took the car this morning to the shop, and the problem seems to be the passenger seat sensor mat, and if true, we're talking removing the seat, upholstery work, the full monty. An expensive proposition. So for now the error code is cleared and the warning light is off. Perhaps, and hopefully, this will be another Gremlin that appeared and disappeared without explanation. Dave, the shop owner, said to avoid putting things on the passenger seat for a while, things like bags, books, etc. Either a proper passenger, or nothing at all. Let the sensor 'rest', so to speak. It costs nothing to try. I'll update again soon.

[trialsmm]

I also received the letter on passenger seat sensor extended warranty on my 2007 Z4 Coupe. Since the sensor didn't work in my car I was very happy. BMW of Macon tested and replaced the sensor pad at no costs and also gave me a 2018 X1 to drive while my car was in the shop for a week! Parts alone would have been $1300.00! Yes I am happy.
I just replaced my leaky radiator and electric water pump my self. Now replacing the starter. Seems like every thing is failing,,,,,,,,,,,,,time will tell how much longer I keep this car.
I like the coupe because it is so rare and different!

[Buddyell]

Resolution !!! I sent in all the info per the letter in February. Received a check for $1200.00 today. I'm impressed!!

[Marcoose]

Another quick update, the warning light reset go-around is still working. Oufda.

[geometrici]

hi I had an 06 z4 3.0si, and had the same problem, the airbag light was coming on and going off, after a while, it came on and never went off. the code I got was for the seat occupancy sensor (got my own scanner) can't exactly remember the code. what I did was I removed the passenger seat out of the car, and tore down the whole seat and removed the seat occupancy sensor, the sensor was tied to the bottom of the seat with around 15 hog rings (you need to get new hog rings and upholstery pliers, you can get them at Walmart or Home Depot), I cut them off and removed the sensor, then I found a used sensor and put it on the seat by using new hog rings. and finally reset the light.

[TractorGuy]

Thanks for reporting your fix geometrici!

We recently bought a 2003 Z4 with the airbag light on. I'm still working on how to get INPA to work and translated to English so I can read and understand the cause. I finally figured out you don't go through the obvious body/airbag that comes up in the menu. You have to go to safety modules then all the sub menu choices under that. I did all that and did a reset but the light remains on.

I am going to try an older version of INPA which I understand will work with the English language. That would greatly simplify the code reading process.

The car also had a service engine light on which I was able to read and clear with a inexpensive Zurich code reader from Harbor Freight. Too bad it wouldn't read the body or safety modules. I am hoping to avoid buying a super expensive code reader just for this car.

[mctayloruk]

I recently purchased the Foxwell NT510 Elite with the BMW package for our '04 3.0i. It was on sale for $129.00. I chose it after reading all the FB and other forums talking about code readers.

After 16 years of faultless driving, I recently had the dreaded dash airbag light come on. The NT510 allowed me to find all the codes in memory and clear out what must have been old ones from when the battery needed replacing. That left the dreaded SBSR passenger side code. In my case, 98F6.

Using the 'live' feature, I was able to get my wife to sit in and out of the passenger seat and watch the code flip from Unassigned to Occupied and the console light (not dash) airbag light come on and off. So that ruled out the passenger seat occupancy wiring issue and a $200 DIY repair.

After reading more online, I disengaged the Battery Safety Terminal on the battery and cleaned the connectors with a can of electronic contact spray cleaner. Those I couldn't open, I sprayed, too, thinking it might seep in. I then reconnected the BST and the battery.

When I turned the car to On the dash airbag red light still came on. However, I ran the Foxwell scan, found the fault again, used the Clear feature, and it has no re-appeared.

I'll drive it for a few days to see if it stays off, but it appears $129 and the FB Z4 forums, this site, and others, may have saved the day.