See also:

Underbody Maintenance
Use plain water to flush dirt and debris from the vehicle's underbody. Your dealer or an underbody car washing system can do this. If not removed, rust and corrosion can develop. ...

Ignition Positions (Key Access)
The ignition switch can be turned to four different positions. To shift out of P (Park), the ignition switch must be in ON/RUN or ACC/ACCESSORY and the brake pedal must be applied. Notice: ...

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 opt ...