Air bag light came on (for no reason)

[johnrando]

Hi. For some reason, ,my airbag light came on yesterday, for apparently no reason. I wasn't doing any work with or near it. So, just to check, i disconnected my battery, pulled their bag out from the steering wheel, the re seated it. The light is still on. Anything I can do outside of taking it into a shop? I guess I could try to read some codes?

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[Avetiso]

Well, unplugging your battery won't do anything, unfortunately. Once the light is there, it has to be manually reset off no matter what. My guess is seat belt tensioner wiring (the part of wiring under your seat with the huge yellow bracket).

I have the reset tool, but it's going to someone in VA right now. :(

[fredo]

Dario, do u think your SRS reset tool can be used on a 2005 mini cooper ?

[Avetiso]

Dario, do u think your SRS reset tool can be used on a 2005 mini cooper ?
Wouldn't surprise me, but I'm not sure. Dane would know, he had for much longer than I did.

[Lanister]

John,

This happened to me also when one of the plugs from the steering wheel air bag just disconnected after about a day of driving following my steering wheel swap. It was my fault for not plugging it in firmly enough. Once the light comes on, you have to clear it using a tool or software like DIS. They all do the same thing. I'll happy to do it for you if you're planning coming up to the bay area in the near future.

[danewilson77]

Dario, do u think your SRS reset tool can be used on a 2005 mini cooper ?

Yes. It would help him diagnose what's causing the trip.

Sent from my S4 > Mason, OH

[johnrando]

Thanks for the tips. I'll see if I can take a look at the under seat wiring. The airbag plugs were in solid on the steering wheel. I'll take the SRS reset tool after whoever has it.

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[fredo]

Yes. It would help him diagnose what's causing the trip.

Sent from my S4 > Mason, OH

That's what I wanted to hear. Thanks, Boss.

[JupiterBMW]

Well, unplugging your battery won't do anything, unfortunately. Once the light is there, it has to be manually reset off no matter what.

I disagree. Way back in the day, when I traded a set of black leather seats and door cards for alcantara ones, I had this occur. The guy I traded with showed up and his airbag light was blinking. We disconnected the battery, swapped everything out, and then when we reconnected his battery and started his car, the airbag light was out. We had done nothing in terms of any diagnostics. Battery was unplugged for a good couple hours I'd say.

That's all the help I've got, sorry, but it's something!


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[Lanister]

Good to know Jon.

[johnrando]

So where is the SRS reset tool going to next?

[Vas]

I dropped it off today at usps to head to Virginia Beach for somebody to use it.

[Avetiso]

So where is the SRS reset tool going to next?

Texted the guy, he said he'll diagnose and ship out, leave for a week, and then he'll need the tool again after. John, is one week sufficient for you?

[Vas]

Just a heads up guys but I will need to have it back sometime as well. I used it to just diagnose my issue as well but I am not in a rush since I still have to order the part and fix the problem.

[Johnmadd]

Passenger seat occupancy sensor possibly?

[LivesNearCostco]

When I got my car the passenger seat occupancy sensor was bad. The SRS light came on and off intermittently. After a shop replaced the sensor mat, the light went off and stayed off without the need for a reset tool. But I heard if you turn the key to On while the seat or an airbag is disconnected, you will need the SRS reset tool to turn the light off. Not sure if true.

[johnrando]

Thanks John. I'll look into that. Vas, why don't you take it and get your work done, then send to me. I'll need time to look into what I need to do to fix it.

[Vas]

When I got my car the passenger seat occupancy sensor was bad. The SRS light came on and off intermittently. After a shop replaced the sensor mat, the light went off and stayed off without the need for a reset tool. But I heard if you turn the key to On while the seat or an airbag is disconnected, you will need the SRS reset tool to turn the light off. Not sure if true.

This is my issue. I just need to order the mat at this point.


Thanks John. I'll look into that. Vas, why don't you take it and get your work done, then send to me. I'll need time to look into what I need to do to fix it.

You sure? I am not in a rush since I have not purchased the part yet and the holidays are coming up.

[johnrando]

Well if you don't need it for awhile, I'll take it next. So, you're replacing your matt? Kinda looks like a pain, but doable.

[Vas]

Well if you don't need it for awhile, I'll take it next. So, you're replacing your matt? Kinda looks like a pain, but doable.

I shall find out when i start replacing it.

But Dario and you should probably get in touch in regards to the tool.

[billschusteriv]

Just had a similar issue in the e46. Luckily my indy mech had a really nice scan tool that could read the airbag codes (along with some other stuff my scan tool couldnt read).

From what I understand, there are airbag sensing points all over our car and any one of them can cause that light to pop.

Johnmadd's suggestion of the passenger occupancy sensor is a common fail point.

The code that mine sent was something like Master Relay. However it was reset over 6 mos ago and hasnt come back.

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[Johnmadd]

Just had a similar issue in the e46. Luckily my indy mech had a really nice scan tool that could read the airbag codes (along with some other stuff my scan tool couldnt read).

From what I understand, there are airbag sensing points all over our car and any one of them can cause that light to pop.

Johnmadd's suggestion of the passenger occupancy sensor is a common fail point.

The code that mine sent was something like Master Relay. However it was reset over 6 mos ago and hasnt come back.

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Bill, do you know what the code numbers were?

[illirep]

I disagree. Way back in the day, when I traded a set of black leather seats and door cards for alcantara ones, I had this occur. The guy I traded with showed up and his airbag light was blinking. We disconnected the battery, swapped everything out, and then when we reconnected his battery and started his car, the airbag light was out. We had done nothing in terms of any diagnostics. Battery was unplugged for a good couple hours I'd say.

That's all the help I've got, sorry, but it's something!


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Joop - not sure if your post implies this or not, but I would assume the light was caused by a faulty occupancy sensor in the seat that was removed. Once the replacement seat went in without a faulty occupancy sensor, I guess the code went away. I would still think the code would need to be manually reset regardless though....

[johnrando]

Good input. I'll run the SRS code reader when I get it to make sure, but research definitely points to that passenger seat sensor as a common failure point.

[Vas]

I was planning on purchasing mine from ecstuning. IIRC they were like $130 for the part.

[derbo]

GT1 can pull the codes too. JR needs a laptop with an obd cable!

Have you tried removing your battery and tapping the positive cable the negative cable?

By this I mean undo both terminals on the battery and touch the two cables together without the battery. Ive had success with newer BMWs clearing lights this way.

sent from a Moto X

[johnrando]

Interesting Derek. I know William has a coding setup. I def want to read the codes before I clear, and the SRS tool will be on it's way soon.

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[johnrando]

OK, I installed the passenger seat airbag bypass just because that was most likely the culprit. Then I plugged in the airbag reset tool and it said code 73 AND 74, which is the Passenger Seat sensor AND the Driver Seat sensor mat error. Any ideas? Strange that the bypass tool didn't at least clear the passenger seat sensor so it must be something else. Why would those two things go off at the same time?

[Vas]

I had no luck with the bypass as well.

Did you hardwire yours in?

[johnrando]

It was a switch I bought off ebay... seller had very good ratings, guaranteed work. But that would only be the passenger side, the code also says it's the driver's side, so it must be something else. (Maybe I should look at cleaning the connectors?)

[Vas]

I bought mine from airbarg rx. Also just plugged in however I wasn't sure if I needed the one that is hardwired.

[LivesNearCostco]

JR: Did you clear the codes and then they came back? I don't think our cars have a driver's seat occupancy sensor... it assumes if someone is driving the car, the driver's seat is occupied! But the driver's seat has a seat belt fastened sensor.

[johnrando]

I did clear the codes and they did come back. That's really strange that there is a code for the drivers seat.

[MrMaico]

I did clear the codes and they did come back. That's really strange that there is a code for the drivers seat.

John, I was just looking at these codes and the #73 looks like it is for drivers seat POSITION sensor. Same deal with the #74, passenger seat position sensor. It looks like there is a separate, different code for the occupancy sensors. Maybe there is a sensor that indicates whether the seat might be tilted forward or not that could be causing your issue? Still seems strange though that they both would go off at the same time.

Barry

[johnrando]

Oh, good catch Barry. Thanks for posting. I'll try to look into that.

[LivesNearCostco]

Didn't know our cars had a seat position sensor--interesting. I thought the driver's side had only a seat belt sensor and the passenger side had a seat belt and occupancy (pressure mat) sensor. Maybe the SRS computer wants to know how close your seat is to the steering wheel, so it knows how hard to deploy the airbag?

[johnrando]

I found this but I'm not sure if it's for ours yet, nor would I know how to replace it.

http://parts.bmwofsouthatlanta.com/products/BMW-3-Series-E21-E30-E36-E46-E90-E91-E92-E93/335is/Position-sensor--seat-BEIFAHRER/1413851/65779125898.html

[LivesNearCostco]

The fitment guide on that page says that sensor is only used for E9x 3-series and E88/E82 1-series, and not until either 2006 or 2011. Doesn't mean we don't have one but seems unlikely we have that one.

[johnrando]

That's what's weird, it lists E46 but then later says it's only for cars you listed, and NOT the E46.

[Silber92]

Well to keep the spirit of Halloween going, I'm bringing this back from the dead.

Did you ever figure out what the issue was John? Or anyone? Hoping there is an easy solution.

I've had the SRS light on since I pulled the driver's seat to have upholstery work done over the summer. Battery disconnected ahead of time and all that. Dario's Peake tool (thanks again for the loan!) shows same codes, 73 and 74. No idea why both codes, didn't touch the passenger seat, and I double checked all connections before the driver's seat went back in. As soon as I clear them, the light is back on.

Like you all, I can't find any hard evidence our cars even have a 'Seat Position Sensor', or at least realoem doesn't list anything so named.

Any ideas? No way do I want to head to the stealership.

[johnrando]

Pm'd you. Sorry, no.

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[LivesNearCostco]

Almost 6 years after replacing my passenger seat occupancy sensor, I'm getting an intermittent SRS light. Had a Peake SRS scanner anyway that would fit only the 20-pin round connector on the E36, so bought a Peake adapter cable and last night read the stored codes in the ZHP. I got 2 codes from table 04: 70 and 50. 70 is "seat occupancy sensor" and 50 is "supply voltage." The light seems to come on more often when driving in wet weather. Wondering if the mat is failing again after 6 years and is affected by humidity? Or maybe the sensor mat plug is loose or dirty. I'll try to plug and unplug the sensor and clear the codes to see what happens.

BTW, once I get this sorted out, the Peake SRS scanner will be available for loan.

Anyone else have the occupancy sensor mat fail after replacement? I thought the replacement ones were more durable than the original ones.