Airbag code 12

Hey guys. Been lurking for a while and have gleaned quite a bit of information from y'all, but I finally found something that my google-fu can't find. Code popped on this morning from the airbag system. Code 12, and while I've found out that(I think) it's "passenger seat belt pretensioner malfunction", I am stumped on how to go about fixing the issue. I know the first step is to pull the battery and reset the computer, the battery that I have is almost dead completely. I was having starting issues last night. So, I'm Leary about pulling the battery completely for fear of it just killing what's left. Anyways, anyone have any idea how to fix the code 12 issue?

Btw, I'm not new to cars or working on cars, just new to mazdas. Income from the world of Toyota trucks and this is my first Mazda.

soooo, figured it out. just a heads up, low battery voltage trips the code 12 for the airbag system. i feel like an idiot.

I have the airbag 12 code, have a new battery so not a voltage issue. The pretensioner is not working properly and the belt is not retracting back unless helped by hand. I opened up the seat belt assembly seems like the coil spring is not doing its job plus it seems like someone played around with the belt assembly as it has signed of being opened before. Any ideas if this can be fixed or has to be replaced.