Just thought I'd add some info to this thread. I have a 2013 dcsb with the JBL Entune w/ navigation. The above method works for me with the only difference being that the audio and the setup buttons bring up diagnostic information. To exit the hidden menu, just hold down the Setup button. Also another menu can be found by 1) press the setup button More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.