Should be possible, provided the correct version of Vag-Com & cable are used.
A sample how-to PDF for an A5 Golf is attached... found through a quick web search (may or may not be similar for the Jetta).
If you are a registered Vag-Com owner:
http://www.ross-tech.com/vag-com/support.html
or
http://www.ross-tech.com/vag-com/discussion.html