There are two ways:
(1) - Free and a little difficult
(2) - Easy and ~$50 for an OBD scanner, OBD Fusion and the $15 enhanced diagnostic add-on
(1) The free method is from the factory shop manual, in the SRC section.
Without any tools you can read the code by counting the airbag light flashing and clear it.
Here are the steps to get the SRS module in diagnostic mode:
Then look up the flash code in the SRC section.
-OR-
(2) Use OBD Fusion to read and reset the code:
Good luck!