Just bought a 2006 with 5000 miles. I already have an XM subscription, and would like to add this unit. I need the XM radio number....book says, "tune to "0" and code will be displayed." This does not work. How would one "tune to zero"? I'm flummoxed.
If your vehicle has the XM radio installed (the audio unit in the dash is XM ready - but does not necessarily mean that the XM option has been installed)
when you select the XM button, XM radio should play on channel 1. Use the tune button to go to channel 0, which will display the XM radio serial number. If you select XM radio, and channel 1 does not come on, it is very likely that the XM option was not installed by the previous owner.
What you see on the roof may just be a cap. The vehicles are equipped to allow the installation of XM, and I don't think Honda engineers felt good about accessory installer's cutting through the roof, so the hole is there from the factory with a blank cover.