There's a process for updating Garmin maps for 2011-2012 and 2013-2014 Chargers using files from a Garmin Nuvi GPS. The other model years can get updated maps from the HERE website. The HERE updates normally cost $149.00 but there's a discounted price until the end of 2018 for $99.00
https://chryslergroup.navigation.com...ChryslerNA/USD
HERE is the company that FCA uses (outsources) to package and distribute the Garmin map updates.