Service Airbag light turned on?

The first step is to have the diagnostic fault codes read and recorded. The people at most auto parts stores will do that for you for free, but most of the time they can only read codes in Engine Computers. Some of them can read codes now in Anti-Lock Brake Computers and Air Bag Computers.

If you have the codes read by your mechanic, he will use a scanner to read the codes in all of the dozens of computers. This article shows that process so you know what to expect:

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

This usually just takes a few minutes. Once you know the fault code(s), post then in your reply, then I'll look up the definitions. That will tell us where to go next.

This has nothing to do with the Check Engine light. The Air Bag light is for that computer and system only. Some of the newer inexpensive code readers are able to access Air Bag (SRS) Computers, but they will only read fault codes. They don't allow for other testing.

I just ran into this article that can probably explain this better than I can:

https://www.2carpros.com/articles/what-an-airbag-light-means