See also:

End a Call
Push . System responds: “Call ended.” ...

Cellular and GPS Antennas
Avoid placing items over or near the antenna to prevent blocking cellular and GPS signal reception. Cellular reception is required for OnStar to send remote signals to the vehicle. ...

Washing the Vehicle
To preserve the vehicle's finish, wash it often and out of direct sunlight. Notice: Do not use petroleum based, acidic, or abrasive cleaning agents as they can damage the vehicle's paint, metal, or p ...