Navigation
OnStar navigation requires the Directions and Connections service plan.
Push 
to receive directions or have them sent to the vehicle navigation screen. Destinations can also be forwarded to the vehicle from Google Mapsâ„¢ or MapQuest.com. The OnStar mapping database is continuously updated. Visit www.onstar.com for coverage maps.
See also:
Recommended Fluids and Lubricants
This maintenance section applies to vehicles with a gasoline engine. If the
vehicle has a diesel engine and/or an Allison Transmission, see the maintenance schedule section in the DURAMAX®
Diesel ...
Maintenance Replacement Parts
Replacement parts identified below by name, part number, or specification can
be obtained from your dealer.
...
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).
†...