2008 GMC Sierra 1500 Pickup Owner's Manual - Page 121

When the System Does Not Seem to Work Properly • The driver disables the system. • The parking brake pedal is depressed. • The ultrasonic sensors are not clean. Keep your vehicle's rear bumper free of mud, dirt, snow, ice and slush. For cleaning instructions, see Washing Your Vehicle on page 5-102. OnStar® System • A trailer was attached to your vehicle, or a bicycle or an object was hanging out of your tailgate during your last drive cycle, the red light may illuminate in the rear display. Once the attached object is removed, URPA will return to normal operation. • A tow bar is attached to your vehicle. • The vehicle's bumper is damaged. Take the vehicle to your dealer/retailer to repair the system. • Other conditions may affect system performance, such as vibrations from a jackhammer or the compression of air brakes on a very large truck. If the system is still disabled, after driving forward at least 15 mph (25 km/h), take your vehicle to your dealer/retailer. OnStar uses several innovative technologies and live advisors to provide you with a wide range of safety, security, information, and convenience services. If your airbags deploy, the system is designed to make an automatic call to OnStar Emergency advisors who can request emergency services be sent to your location. If you lock your keys in the vehicle, call OnStar at 1-888-4-ONSTAR and they can send a signal to unlock your doors. If you need roadside assistance, press the OnStar button and they can contact Roadside Service for you. 2-45