impala2k3

The Service Airbag soon light has come on twice in the past 2 weeks and stay on. If you shut the car off & turn it back on, the light goes out & doesn't come back on. I called onstar & while it was on and there was a trouble code. After it shut off and the light went off, I called them again & onstar said that it didn't store any codes. My concerns are if there is an issue, is there any warranty after 36k mi on the airbag system as my car has a little under 48k mi and where it has been a random thing, should I be concerned and take the car to a dealership or wait until it will not shut off.

Thanks