This is something I am hoping I can get some additional people to test for me. Someone posted a very good comment in one of the other threads on this topic around a lot of people seeming to have the issue at about the same general timeframe. What that got me thinking about was something possibly Sirius related with either new channel info or other data that is 'broadcast' to all receivers in one go. Could possibly be tied to a free preview weekend when everyone's receivers are re-enabled. As my own personal test I had been intending to downgrade my own subscription (from the All Access + Traffic + Nav + Weather down to Mostly Music + Traffic + Nav + Weather). Did so and after leaving work I did the refresh requested and once I saw 'Subscription Updated' in the lower left quadrant it went to the telltale no audio, won't toggle off or on, and won't change sources. Stayed that way for the whole 15-20 minute drive. Granted after coming home and parking it for 5-10 minutes it seemed to come back without me pulling fuses.
If anyone is willing to test this for me, and be prepared to do a fuse 79 pull, is this:
If you have a subscription either a) If you are planning to change/update your subscription, go ahead and do so and refresh. or b) Do a refresh anyways if not planning to change subscriptions.
Additionally if you have access and the knowledge to utilize Forscan, the model and calibration info for the ACM would be beneficial.
I'm going to see if I can pull any documented info on updates Sirius has sent out over time to correlate. I'm very interested in seeing if there's something to this being a possible cause.