I've had my Z1 since it first came out sept 2006 and overall been pretty happy with it intill today . I started up my Truck drove off and one min into my drive I heard a hum type noise coming out of my speakers. I then tryed to lower the sound to next to zero and the noise wouldn't go away at all. I pulled over and did a reboot and same issue again noise started up as soon as my key hit (acc) .

 

I had my z1 installed on a 2004 Tundra and overall everything has been working up till today. I have the bluetooth option and Xm navi traffic installed under the seat. My biggest guess is the ground wire on the Xm unit is connected to the seat bolt and I feel in some way that might have been pulled out due to the fact I was pulling the seat back. That's my only guess so far. I pulled out the 15 amp fuse because I didn't want to bother with that noise on my drive to work and I had no control on that noise from the headunit on this sound from the speakers. Coming home today I placed the 15 amp fuse back on and everything is working again back to normal. I do plan to check out the wiring again at my friends house whom installed it .My friend comes to the ideal it sounds like the ground wire used for the xm brain came loose.