OnStar Technology

With more than two million subscribers, OnStar is the leading provider of telematics services in the United States. Telematics is the transmission of data communications between systems and devices. OnStar's in-vehicle safety, security, and information services use Global Positioning System (GPS) satellite and cellular technology to link the vehicle and driver to the OnStar Center. At the OnStar Center, advisors offer real-time, personalized help 24 hours a day, 365 days a year.

Find out more about OnStar technology:

GM OnStar Automatic Crash Response System (ACR)
GM Vehicles Equipped with ACR
How You Stay Connected
OnStar Equipment
GPS Technology

GM Automatic Crash Response System (ACR)

Figure 1: The GM Automatic Crash Response (ACR) system uses front and side sensors as well as the sensing capabilities of the Sensing and Diagnostic Module (SDM) itself. The accelerometer located within the SDM measures the crash severity.

Figure 2: In the event of a moderate to severe frontal or side-impact crash, data is transmitted from the affected sensors to the SDM. The SDM sensor also can identify a rear impact of sufficient severity. Regardless of whether the air bags deploy, the SDM transmits crash information to the vehicle's OnStar module.

Figure 3: Within seconds of a moderate to severe crash, the OnStar module will send a message to the OnStar Call Center (OCC) through a cellular connection, informing the advisor that a crash has occurred. A voice connection between the advisor and the vehicle occupants is established. The advisor then can conference in 911 dispatch or a public safety answering point (PSAP), which determines if emergency services are necessary. If there is no response from the occupants, the advisor can provide the emergency dispatcher with the crash information from the SDM that reveals the severity of the crash. The dispatcher can identify what emergency services may be appropriate. Using the Global Positioning System (GPS) satellite, OnStar advisors are able to tell emergency workers the location of the vehicle.

Number and location of sensors and SDM may vary depending on vehicle model.

GM Vehicles Equipped with ACR

ACR Availability Model Year 2008
Buick	Chevrolet	GMC	Pontiac
Enclave	Avalanche	Acadia	G5
Lucerne	Cobalt	Canyon	G6
	Colorado	Denali	G8
Cadillac	Equinox	Denali XL	Solstice
CTS	HHR	Envoy	Torrent
DTS	Impala	Envoy XL
Escalade	Malibu	Envoy XUV	SAAB
Escalade EXT	Malibu Maxx	Sierra	9-7x
Escalade ESV	Monte Carlo	Yukon
SRX	Silverado	Yukon XL	Saturn
STS	Suburban		AURA
	Tahoe	Hummer	OUTLOOK
	Trailblazer	H2	SKY
	Trailblazer EXT	H2 SUT	VUE
	Uplander	H3

ACR Availability Model Year 2007
Buick	Chevrolet	GMC	Pontiac
Lucerne	Avalanche	Acadia	G5
Rainier	Cobalt*	Denali	G6
Terraza	Equinox	Denali XL	Solstice
	HHR	Envoy	Torrent
Cadillac	Impala	Envoy XL
DTS	Malibu	Envoy XUV	SAAB
Escalade	Malibu Maxx	Sierra	9-7x
Escalade EXT	Monte Carlo	Yukon
Escalade ESV	Silverado	Yukon XL	Saturn
SRX	Suburban		AURA
STS	Tahoe	Hummer	OUTLOOK
	Trailblazer	H2	RELAY
	Trailblazer EXT	H2 SUT	SKY
	Uplander	H3	VUE

ACR Availability Model Year 2006
Buick	Chevrolet	GMC	Pontiac
Lucerne	Cobalt*	Envoy	G6
Rainier	HHR	Envoy XL	Montana SV6
Terraza	Impala	Envoy XUV	Solstice
	Malibu
Cadillac	Malibu Maxx	Hummer	SAAB
DTS	Monte Carlo	H3	9-7x
SRX	Trailblazer
STS	Trailblazer EXT		Saturn
	Uplander		RELAY
			VUE

ACR Availability Model Year 2005
Buick	Chevrolet	GMC	Pontiac
Rainier	Cobalt	Envoy	G6
	Malibu	Envoy XL
Cadillac	Malibu Maxx	Envoy XUV	SAAB
STS	Trailblazer		9-7x
	Trailblazer EXT

*Excluding SS

How You Stay Connected

Contact OnStar using the three-button system
Establish direct voice contact with an OnStar Advisor using the built-in microphone, cellular antenna in your vehicle, and cellular network
An Advisor can pinpoint your location using GPS technology. (Based on model availability.)
If your air bag deploys, a message is sent to the OnStar module in your vehicle. The OnStar module then contacts the OnStar Call Center.* (Based on model availability.)
OnStar module connects vehicle computer to OnStar via cellular antenna
Cellular antenna connects vehicle through cellular network

OnStar Equipment

All OnStar-equipped vehicles have one of three types of equipment, based on wireless network technologies:

Analog-Only:
OnStar-equipped vehicles with analog-only equipment were designed to operate only on the analog wireless network and cannot be upgraded to operate on the digital network. Vehicles with this equipment will no longer be able to receive OnStar services beginning January 1, 2008. At that time, service will be available only through dual-mode (analog/digital) equipment. Analog-only vehicles cannot be upgraded to digital equipment.
Analog/Digital-Ready:
OnStar-equipped vehicles with analog/digital-ready equipment operate on the analog wireless network, but can be upgraded to dual-mode (analog/digital) equipment if available for that vehicle. Beginning January 1, 2008, OnStar service will not be available on these vehicles unless the OnStar equipment has been upgraded to dual-mode (analog/digital) equipment.
Dual-Mode (Analog/Digital):
OnStar-equipped vehicles with dual-mode (analog/digital) equipment operate on both the analog and digital wireless networks and will not require an upgrade in connection with the wireless industry's transition to the digital network.

GPS Technology

How GPS Works

Global positioning system (GPS) satellite technology measures how long it takes a radio signal from a satellite to reach a vehicle, and then calculates distance using that time. OnStar uses the latest GPS receiver and antenna technology to get the most accurate vehicle location. Additionally, in some vehicles the wheel speed and direction are also used to further enhance OnStar's ability on location technology.

OnStar services require vehicle electrical system (including battery), wireless service and GPS satellite signals to be available and operating for features to function properly. Subscription Service Agreement required. Call 1.888.4.ONSTAR (1.888.466.7827) or visit onstar.com for OnStar's Terms and Conditions, Privacy Statement and system limitations and details. Additional information can be found in the OnStar Owner's Guide.