The Office of Defects Investigation (ODI) opened this investigation based on reports that the doors were failing to properly latch on model year (MY) 2009 Mazda6 vehicles.Complainants alleged that the door would fail to latch, or would not properly latch. ODI received a total of 9 complaints alleging this condition primarily on the front side doors, however any of the four side doors could be affected.In response to ODI's Information Request, Mazda provided 56 consumer complaints related to the alleged problem, and 329 warranty claims.On September 23, 2013, Mazda notified ODI that it would conduct a safety recall on model year 2009-2013 Mazda6 vehicles built from February 4, 2008 through August 24, 2012. This period covers the start of production of the MY 2009 Mazda6 through the end of production for the 2013 model year and totals a population of approximately 161,400 vehicles. Mazda determined that the door latch mounting screws may become loose due to lack of torque during manufacturing and/or unevenness of the door shell in the latch mounting area. If all three door latch mounting screws become loose, the door latch mechanism may not engage, potentially resulting in the doors opening while the vehicle is in motion.To remedy the condition, a thread locking adhesive will be applied to the latch screws on all side doors, and the screws will be tightened to the specified torque.This investigation is closed on the basis of Mazda's announcement of safety recall 13V-425.ODI reports cited above can be reviewed at www-odi.nhtsa.dot.gov/owners/SearchNHTSAID under the following identification (ODI) numbers: 10406174, 10448036, 10492403, 10503682, 10508051, 10515258, 10521830, 10535228, 10544489.