When Monitored:
WARNING: This page is about a different car, the 2011 Jeep Liberty. However, it is still accessible from the selected car via links, so may be relevant.
With the CAN ignition status as IGN_RUN, the Occupant Classification Module (OCM) tries to detect potentially damaging events and monitors the CAN Bus for the Impact messages (crash event causing one or more airbag or pretensioner to deploy) or upon detecting an Offset Event (if equipped).