Reactivation for Subsequent Owners
Push 
and follow the prompts to speak to an Advisor as soon as possible after acquiring the vehicle.
The Advisor will update vehicle records and will explain the OnStar service offers and options available.
See also:
Security Light
The security light should come on briefly as the engine is started. If the system is working normally, the indicator light turns off. If it does not come on, have the vehicle serviced by your dealer ...
Traction Off Light
This light comes on briefly while starting the engine. If it does not, have the
vehicle serviced by your dealer. If the system is working normally, the indicator
light then turns off.
The tract ...
How to Check Automatic Transmission Fluid
Notice: Too much or too little fluid can damage the transmission. Too much can mean that some of the fluid could come out and fall on hot engine parts or exhaust system parts, starting a fire. Too lit ...