seems a common thread, however in my case, the head unit shows grey on the sub woofer control. worked fine for years, then stopped, no sound. and was not testing, so replaced that, now only visable issue is the sub woofer is grey while all other controls work. Reeplace sub? bad connection? any thoughts?
thanks

 

I don't have the nav system, but mine has just died too. Going to Jaguar on Friday to get sorted!