Fixing the airbag light - seat belt pretensioner error code

Recently my airbag light randomly came on. After searching around on the site I realized the only way to accurately diagnose the issue is with a airbag code reader/reset tool. Ken at www.Bimmertools.com hooked me up and in a few days I had a shiny new tool.

https://secure.4siteusa.com/WhatsYou...categoryID=146

Here is how I fixed the common seat belt pretensioner issue. My searching turned up an interesting issue. Often times the pretensioner itself isn't bad, just the wiring. I was hoping this was the case because the wiring is much cheaper than the pretensioner. I had a spare wiring harness handy. If you don't (why would you) I would suggest ordering one (approximately $15) and trying this before you invest in a new pre-tensioner.

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** Use this at your own risk **
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1) This is what I started with


2) Here is my brand new Peake tool from BimmerTools.com


3) Plug in the Peake too to the OBD port that is in the drivers side foot well. This should be attached to the underside kick plastic....but mine isn't...yeah.


4) Read your codes following the directions that came with the tool, very simple.


5) My code was table 10, code 02 which is drivers side pre-tensioner.

6) Start by disconnecting the battery.


7) Disconnect the under seat connector freeing the seat from the wiring harness. You can pop the connector open by using a screwdriver to move the slider/lock over towards the centerline of the car. You can see the lock is moved over a finger width in the first picture. In the second picture you can see the lock all the way out (next to my thumb).


8) Unbolt the rear two seat bolts.


9) Remove the plastic caps covering the front seat nuts.


10) Remove the front seat bolts.


11) Remove the seat headrest, tilt the steering wheel up and push it all the way in. Lift the seat up and rotate it around and sneak it out the door. If you have a sedan you can leave the seat belt attached to the seat. I set the seat just outside the door.


12) Remove the wiring harness from the pre-tensioner.


13) Remove the wiring harness plug from under the seat by pressing the two clips on either side to release it, the slide it back. Look at the second picture to understand what you're trying to unclip.


14) Cut the one zip tie that holds the wires and undo the other wire holding clip.

15) Remove the black shield part of the connection. You need to pull back the clips on both sides. The clip is just at the tip of my thumb.


16) Take your new wiring harness and connect it to the pre-tensioner. Don't worry about routing the wires under the seat yet. We want to test the new wiring harness before we bolt everything back together.

17) Plug the yellow connectors together reconnecting the pre-tensioner to the car. I rigged it up so I could plug in the seat while it was sitting outside next to the door.


18) Reconnect the battery, reconnect the Peake tool, clear the codes and cross your fingers!


19) Success!


20) If you're airbag light is still on disconnect the battery and recheck all your connections, try reseating all the connectors, plugs, etc and test again. If your airbag light is still on then you're going to need to order the pre-tensioner. Bolt everything back together for now until you get the new parts.

21) Assuming the lights off it's now time to put everything back together.

22) Disconnect the battery and then disconnect the seat wiring.

23) Route the wiring on the seat back in the correctly (reverse of how you took everything apart), mount the yellow plug back under the seat and you're ready to mount the seat again.

24) Put the seat back in, bolt it down, reconnect the wiring, reconnect the battery, etc.

25) Done and done, congratulations!

Shameless bump. I made this thread a long time ago but with out images. We just recently upgrade the photo section to allow for the handy thumbnails, so I put in the images and it is good to go.

Hope this helps, it would have really helped me.

Tim

Nice post about a cheap fix!

Great write-up...you just saved me $200 bones. I just completed the DIY in about 1.5hrs and took the time to clean everything under the seat area.

Thanks!

what is the part number of the wiring harness?
where did you buy it?

Usually its the seatbelt tensioner itself that's faulty... and I haven't gotten around to fix mine yet... I really hope its a cheap fix like the window regulator and the zip tie trick! hahaha.

Tim, how did you test to make sure that it was the plug itself at fault? Multimeter? or something....? Please let me know.
Great write-up btw!

Thanks,
Steve
ASPTuning

the seatbelt tensioner cost around $15. its easy to fix.

Great DIY as usual, Tim.

However, this coder reader/reset tool isn't compatible w/ my '04 3 series. Ken told me that the '04 E46 has a new ECU and the Peake tool won't work w/ it. Are you guys familiar with any other tools that would be compatible w/ my car? Thanks-

I like my Autoenginuity laptop based diagnostic tool.
I needed an airbag reset tool and I needed a SES reset tool and together the two totalled about $200, so I bit the bullet and have never regretted the $500 investment. I figure I'm going to keep my M forever, so I may as well know what's going on and not depend on the dealer.
http://autoenginuity.com/products.html

Here's a list of all the systems you can diagnose with the expanded BMW module. Not just a code reader and reset tool. Enjoy!

http://www.autoenginuity.com/BMW-All-Systems-List.html

Originally Posted by benfano

what is the part number of the wiring harness?
where did you buy it?

Need to bump.

Anyone know the part number of the wiring harness and/or seatbelt tensioner (drivers side)?
Thanks.

B....U....M....P
I need the p/n for the harness too. Replace the cheap stuff first.

Originally Posted by blank1984

B....U....M....P
I need the p/n for the harness too. Replace the cheap stuff first.

I replaced this cable last month and didn't see SRS light anymore.
About $14.00 P/N 52108255704

I also want to sell the srs scanner R5/SRS, because i don't use it anymore, $105 shipped

replaced it and i still have the light.
is there a way to reset it w/o the srs tool? i had one, but it wouldn't work with my car. and, the "disconnect the battery and turn the flashers on 'til the modules drain" won't work because the flashers won't work with the battery disconnected.
any ideas or should i just bring it up to the stealership and get boned $100, for it to possibly still be jacked up?

Nice DIY. My airbag light flickers on and off when a passenger is sitting in the seat. Not sure why it's doing that.

Originally Posted by blank1984

replaced it and i still have the light.
is there a way to reset it w/o the srs tool? i had one, but it wouldn't work with my car. and, the "disconnect the battery and turn the flashers on 'til the modules drain" won't work because the flashers won't work with the battery disconnected.
any ideas or should i just bring it up to the stealership and get boned $100, for it to possibly still be jacked up?

I bought the scanner/reset tool from one of sponsor in here, $120 shipped.
After i replaced this part, i scanned and then reset it with this tool.
I sold the reset tool last week $115 on ebay.
So, you can do the same, or you can buy the reset tool from other fanatics
http://forum.e46fanatics.com/showthr...srs+reset+tool

Originally Posted by benfano

I replaced this cable last month and didn't see SRS light anymore.
About $14.00 P/N 52108255704

I also want to sell the srs scanner R5/SRS, because i don't use it anymore, $105 shipped

I didn't know the wiring harness came with that yellow part. I've updated my DIY removing a couple un-needed steps

Tim

I just did this swap without taking the seat out since I couldn't find the right size wrench to get the seat bolts out...

Anyways, a lot of it was by touch but it is possible!

Originally Posted by yoda2

Nice DIY. My airbag light flickers on and off when a passenger is sitting in the seat. Not sure why it's doing that.

I have the same issue.

Originally Posted by malina

I have the same issue.

Mine too, and making me nervous...specially during the night

Tim, thanks to you I had a big win today. SRS light was dispatched w/o a problem. This only took me 25 minutes, $16, and i didn't even have to take the seat out of the car, i just maneuvered it so that the base was forward and the back was to the drivers side. Thanks again.

- Joe