TSB's are sent to the dealer by the manufacturer if a problem has been found, but not big enough to become a nationwide recall. It's always a good thing to periodically check and see if there are any bulletins on any of your vehicles.
http://www.alldata.com/recalls/
http://www-odi.nhtsa.dot.gov/cars/problems/tsb/tsbsearch.cfm
http://www.alldata.com/recalls/
http://www-odi.nhtsa.dot.gov/cars/problems/tsb/tsbsearch.cfm