ColdFace

I recently purchased a 2008 535xi that was in a prior accident where both front airbags were deployed. I replaced both bags and seat belt buckles. The last thing that remains is battery positive cable. For the time being while I am searching for that cable, I've installed a resistor to trick the system to think that it has a good battery cable in place.
I recently went to my local dealer to reset the air bag light, but for the reasons I am trying to figure out here, they could not do it. They flashed the system, but then all codes came back. I mean they tell me that pretty much every air bag code that is possible is poping up. The service advisor is very unhelpful. He tells me that they have no idea what happened to the car and in order for them to diagnose it, they would need to start checking pretty much everything around the car. He tells me that they got codes for roof air bags, which were not deployed. I know and told the guy what was done to the car, but he's just too new, I guess.

So my question, is there a central connection of some sort that would isolate all air bags from their computer?
I would assume that the air bag computer might be fried, but since it records codes, it should be OK.
Can my resistor fix trip the whole system to throw out all of the codes?

They charge $125/hour and the guy told me that they would need at least 1/2 a day to poke around. What should I do? The car still has a factory warranty. I need to at least put a good cable in before I bring it back.

pauliehcfr

I don't think your resistor trick is going to work because the positive battery cable is actually a small pyrotechnic that deploys when an airbag is deployed. Look where the 2 halves have separated, you should see a small box with an airbag connector. What you have done would be the same as removing an airbag and installing a resistor to "fool" the airbag control module. The system works on sensitive voltages and I guarantee that you have not acheived the proper resistance in the system. Also, don't forget to change the crash sensors mounted on the front bumper reinforcement.

ColdFace

The resistor trick worked on a 2007 328 before, but maybe 5-series are more complicated in this sense.
As far as the front sensors, do they always go bad? I replaced one because it was damaged, but left the other one since it was fine.

Any ideas on why I am having codes for things I know did not deploy?

5FOUR5

Do you have an ohn-meter, access to your vehicles electrical diagrams, air bag code reader, along with electronics back ground? Air bag diagnostics is a very lengthy process that requires every bit of patience and dilligence. Improper diagnostic techniques or pricedure could possibly lead to further damage or serious injury to you or other electrical components. If you are not comfortable with any of the afforentioned elements, I suggest that you find a experienced and reputable indie and be ready to pay 2-4 hours labor, and up to $150 in parts. I doubt that the existing manufacturers warranty will cover any air bag components, since the vehicle has been in an accident. Your concerns could be as easy as replacing a tensioner/ pretensioner, to replacing the canbus module, or a $50 reflash of the air bag module. It would help if you could scan and post all work orders related to the recent repairs performed to the air bag system. You can verify the condition of your power cable by removing plug connector X10179 and testing for battery voltage @ pin 21

ColdFace

Thanks for your responses 5FOR5. I don't have any of the mentioned above tools. I know that I replaced both front airbags, both front seatbelt pretensioners and a passenger side front crash sensor. Yesterday I bought an undamaged battery cable and once it comes, I will put it in and bring the car back to the dealer for another scan. Hopefully it will clear any errors and I won't have to buy a new canbus module.

The dealer did not give me any specific print out of air bag errors from the scan last week, so I don't have that information to post. I will see how it goes this time. I was just a bit alerted when my service advisor told me that they had ALL the possible codes in there: even for those bags that did not blow ...

krisaowa

I think the problem is that of your resistor. Once you replace your SBK positive cable, I would hope that the errors go away. Besides, SBK error mentions general failure of SRS and not specific (driver / passenger / etc). So its the cable I think.

Good luck and lemme know what the issue is/was over PM.

Thanks!

kris