check engine light

One sequence:
1)Go to dealer
2)Have dealer check diagnostic code
3)Have dealer fix problem
4)Have dealer turn off code and check to assure the problem is fixed...

Sorry, but you didn't provide much information and that sequence is the best IF you don't know what caused the code.

Another sequence:
Drive the car--often 3 start/stop (off/on) cycles will clear simple codes--when my XM radio was installed they unhooked the Power button or did some other minor thing that caused the triangle/exclaimation to occur. When I drove the car through 3 cycles of starting/driving and shutting down it cleared itself. I think the same thing happens if you don't quite tighten the gas cap down completely.

Finally:
If you ran out of gas or something more significant, but now you know it is corrected, I believe you can just briefly disconnect the 12V battery and reconnect it to clear most codes. Now, you'll lose all presets in your NAV, radio, BT Phone book, current tank miles, etc., but the warning 'should' be gone.