My car's Check Airbag light came on. I had earlier tried to determine the cause with a friend's OBII scanner but wasn't able to pull any error codes at the time. I had to bring my car to a dealership to get an unrelated safety recall fixed, so I finally asked the mechanic to look at the airbag light for me. I'm guessing he just plugged in his scanner and with 5 minutes of labor determined the cause was a faulty clock spring. They charged me $130 just for that diagnostic. Further googling pinpointed the clock spring was the exact cause because of the fact that the light would shut off if the steering wheel was turned all the way to one side (in hindsight I clearly should've done more research before having the dealership look at it).
The dealership quoted me $700 to replace the clock spring, but they would credit the $130 they already charged me to that total.* I declined and googled the fix. It turns out the replacement part costs about $50 and I found this video showing the process:
https://www.youtube.com/watch?v=2pISb-WDHi8
My landlord had all the necessary tools, just run of the mill sockets and a torx wrench. My landlord came out when I was working on the car and asked if I was a mechanic. He seemed impressed with the fact I had removed the steering wheel. It probably took me an hour total because I spent 10-15 minutes wrestling with the steering wheel bolts, but after that it was pretty smooth sailing.
After completion, I turned on the car and took it for a test drive. No more airbag light.
* = They also tried to tell me that my clutch was starting to go even though it was replaced less than a year and 8k miles ago. This is example #105456 of why to never take a car to a dealership for repairs, but I didn't have many options because I needed the safety recall fixed and other mechanics I talked to didn't want to deal with airbag issues.