I wanted to share something I just found out this weekend when I took my 2009 Toyota Corolla in to the dealership. Problem was that I was hearing a loud humming sound in the cab. I could tell it was coming from the rear of the car. In addition, my airbag light went on. The problem was that my driver side rear axle bearing was out. Cost for the job, approx. $700. The continuously lit airbag light was fixed by installing a clock spring? Cost $150.00. My husband purchased the extended warranty, so we only had to pay $50. My car drives and rides a lot better now, and it's quiet.