I have Xm and Sirius daisy chained to my Z2. This morning, i turned on my radio and the XM was fine. I switched over to Sirius and there was nothing coming through. When i switched back to XM, the sound is muted. I had to turn the car off and back on to get the XM sound back...tried again and it happened again.

Everything worked perfectly fine last night. any ideas?

took it in yesterday and got it fixed. There was an issue with the sirius Pioneer unit. replaced everything works now.