See also:

Ignition Transmission Lock Check
While parked, and with the parking brake set, try to turn the ignition to LOCK/OFF in each shift lever position. The ignition should turn to LOCK/OFF only when the shift lever is in P (Park). ...

Immobilizer
See Radio Frequency Statement  for information regarding Part 15 of the Federal Communications Commission (FCC) rules and Industry Canada Standards RSS-GEN/210/220/310. ...

Multi-Band Antenna
The multi-band antenna is on the roof of the vehicle. The antenna is used for the AM-FM radio, OnStar, the XM Satellite Radio Service System, and GPS (Global Positioning System), if the vehicle ha ...