2006 XJ8 with Nav, have factory installed Sirius, not subscribed. I've never heard anything, I thought it was because I hadn't subscribed, but it turns out there's a Preview channel that everybody should be able to listen too. I've never been able to use it, FM transmitter just puts out silence.

How do you select Sirius?

 

Park the car out in a clear area (ie don't try this in your garage)

I'm not at the car right now but basically you select "menu" on the sirius..... you scroll down to FM frequency and note the frequency. Check that FM transmit is "on" in the menu. You should also scroll to signal strength in the same menu and make sure you have bars showing for "SAT" and "TER" Then you select channel 184 on the sirius. Then you tune your FM radio to the FM frequency you noted earlier. If all that works, you should be able to hear the demo music from sirius through your car stereo. Do you have the remote for the sirius ? (I'm not sure how to select channels from the unit itself.... I use the remote and just type 184 enter and it changes to channel 184.

You can tell whether the sirius unit is broadcasting anything because when you are on FM, if you switch the unit of and on, you should hear a difference in volume on the FM radio

I spent about 3 weeks on mine trying to activate it, but the end result was I never got any signal bars on the "TER" meter so I couldn't receive the signal to activate it, so I gave up. I'm assuming there's some fault in my unit. I may go back later and have a look at the brain thats in the trunk, but for now I'm just listening to MP3s

 

I've done that, but all the FM transmitter puts out is silence. The default channel is 184, and I have SAT and TER signals. I have no idea what's wrong so far.

 

I know my sirius worked but did not keep the subscription. When it ended, it went silent. Just went to the car now and tried 184 and got perfect silence. I did not find a channel that had any sound but did not try them all. I suspect yours would work if you were subscribed.