I was just browsing the Caddy site and saw a pic of the CTS Nav screen. For the life of me, I don't know what GM was thinking, but it appears that the system is different than the Denso that our SRX uses.
My only suggestion would be, if you do not have the musical note button, to hold whatever buttons you do have down for 3-5 seconds, and see what appears---if anything.
If it's not a Denso, you're basically on your own.
