An airbag sensor being unplugged would do that from what I understand, as well as the plastic strip that winds around inside the steering wheel being broken. This happened in our 850 and we had to have it replaced. Wasn't that big of an undertaking.
Sorry for the delay..I'm a newcomer. I removed my drivers seat to tighten up loose supports. It began to rain so moved inside my garage. Starting my car with removed seat caused SRS light to come on. Had to have system re-programed<br>roncop