GMC 2003 Sierra 1500 Pickup Owner's Manual page 260

XMTM
Radio
Messages (cont'd)
y
Message
I
Not Found
XM Locked
message after having your vehicle serviced, check with the
servicing facility.
Radio ID Radio ID label If you tune to channel 0, you will see this message
(channel 0) alternating with your XM Radio 8 digit radio ID label. This
label is needed to activate vour service.
Unknown
Radio ID not known
(should only be if
hardware failure)
If you receive this message when you tune to channel 0,
you may have a receiver fault. Consult with your dealer.
Hardware failure If this message does not clear within a short period of time,
3-1 05