Buick 2004 Rendezvous Owner's Manual page 222

Radio Display
Message
Radio ID
Unknown
Chk XMRcvr
3-82
XM™ Radio Messages (cont'd)
Condition
Radio ID label
(channel 0)
Radio ID not known
(should only be if
hardware failure)
Hardware failure
Action Required
If you tune to channel 0, you will see this message
alternating with your XM Radio 8 digit radio ID label. This
label is needed to activate your service.
If you receive this message when you tune to channel 0,
you may have a receiver fault. Consult with your dealer.
If this message does not clear within a short period of time,
your receiver may have a fault. Consult with your retail
location.