Hey guys!! I do believe this is my first post to the forums here. Well I have a 2005 525i that I bought 5 years ago. It's got 144k miles on it. Not too many problems with it. Alternator, starter, key went bad, ect... I love this car.
The airbag light is on and has been on for a while now. I couldn't surely connect it to any maintenance that I had recently performed except when the alternator went bad and I replaced that and the battery. I'm stumped. I had my buddy with a scanner pull the codes and I have 3 of them. 281c 281d 299b
I tried a lot of things.
1. I bypassed the seat occupancy sensor and seat-belt latch.
2. Then I verified that the recall for the positive terminal is done.
3. I fixed my broken negative terminal that was rigged up and held on with a pair of vice grips by replacing the post with a post that I ordered from VW
4. Then I bypassed my BST with a 2 ohm resistor.
I've replaced/bypassed everything that I can see from all the research that I've done and getting very irritated now. Any ideas?

 

IDK if this will help but I found it a while ago. Like I said, I have exhausted all my resources and I don't think the stealership will like troubleshooting with all the stuff I have bypassed lol
Oh and the alternator I installed is an "ultima" 11083 alternator. 150A re manufactured.

 

A number of Google entries seem focused on BSD errors being somehow related to the alternator and voltage regulator.

 

Thank you for that direction. The problem is that I don't want to replace my alternator AGAIN for $250 because it might be bad. I wish there was a way to tell for sure because it checks good at OReilly's on the car.

 

O'Reilly's test isn't going to include the BSD (bit serial data). This may or may not be your issue. On BMW, best to stick with parts from BMW itself or original manufacturers to BMW -- in this case, probably Bosch, could also include Valeo.