2008 MDX - XM Functions Vanished

First post - sucks it's 'cause of a problem. I bought the '08 MDX new, and this is only the second or third significant issue... and the first outside of the warranty.

The XM just sort of vanished. The button on the dash does nothing - same for the "Audio" button. And scrolling with the "Mode" button, just skips XM. Any idea what may have happened? Did the XM module die?

Thanks.