Not sure if you have RNS310 or RNS315? 
 
when you press NAV button without any card inserted:
 
RNS310 - will ask navigation data source
RNS315 - has pre-installed map in internal memory and will show map without navigation card.
 
Compatible Cars :
 
Amarok: 2010 – 2016
Beetle: 2012 – 2014
CC: 2011 – 2015
Caddy All Variants: 2010 – 2016
California: 2010-2016
Caravelle: 2010-2016
Multivan: 2010-2016
Transporter: 2010-2016
EOS: 2011 – 2016
Golf All Variants: 2010-2014
Passat: 2011 – 2014
Polo: 2010 – 2014
Scirocco: 2012 – 2014
Sharan: 2011 – 2015
Tiguan: 2013 – 2015
Touran: 2011 – 2015
 
Coverage : 
 
Andorra, Belgium, Denmark, Germany, Finland, France, Gibraltar,Greece, Ireland, Iceland, Italy, Liechtenstein, Luxembourg, Monaco, Netherlands, Norway, Austria, Poland, Portugal, San Marino, Sweden, Switzerland, Slovakia, Slovenia, Spain, Czech Republic, Hungary, Vatican City, United Kingdom.