See also:

Vehicle and Power Issues
OnStar services require a vehicle electrical system, wireless service, and GPS satellite technologies to be available and operating for features to function properly. These systems may not o ...

Compass Calibration Procedure
1. Before calibrating the compass, check that the compass zone is set to the variance zone in which the vehicle is located. See “Compass Variance (Zone) Procedure” earlier in this section. ...

Accessories and Modifications
When you add non-GM accessories to your vehicle they can affect your vehicle’s performance and safety, including such things as, airbags, braking, stability, ride and handling, emissions systems, ...