GM's OnStar Service: How Does It Work?

OnStar mirror interface
OnStar's simple three button interface provides access to hands-free calling, operator-assisted navigation, and emergency services. Image courtesy of hbc4511

What is OnStar?

OnStar is a subsidiary corporation of General Motors that provides a variety of in-vehicle services, which are all delivered via a CDMA cellular connection, but it is also the name of a service that is available in new GM family vehicles. Some of the services available through the OnStar system include turn-by-turn navigation instructions, automatic crash response, and roadside assistance.

All of these features are accessed by pressing a blue “OnStar” button, a red “emergency services” button, or a hands-free calling button.

General Motors established OnStar in 1995 with cooperation from Hughes Electronics and Electronic Data Systems, and the first OnStar units were made available in several Cadillac models for the 1997 model year. OnStar is primarily available in GM vehicles, though a licensing agreement also made OnStar available in several other makes between 2002 and 2005. A stand-alone unit was also released in 2012, which provides access to some of the OnStar services.

How Does OnStar Work?

Each OnStar system that’s installed as original equipment is capable of gathering data from both the on-board diagnostics (OBD-II) system and built-in GPS functionality. They also use CDMA cellular technology for voice communications and data transmissions. Since OnStar subscribers pay a monthly fee for the service, there are no additional charges from the carrier that handles the voice and data connection.

However, additional charges are incurred for hands-free calling.

In order to provide turn-by-turn directions, GPS data can be transmitted via the CDMA connection to the central OnStar system. The same GPS data can also be utilized for emergency services functionality, which allows OnStar to summon help in case of an accident.

OnStar is also capable of transmitting data from the OBD-II system. This can allow OnStar to track your mileage for insurance purposes, provide you with vehicle health reports, or even determine if you’ve been in an accident. Since you may find yourself unable to reach your cell phone after a serious accident, the OnStar call center is notified when the OBD-II system determines that your airbags have gone off. You may then request assistance if it’s needed.

What Are the Available Features?

OnStar requires a subscription in order for it to work, and there are two different plans available. The less expensive plan omits features that are related to convenience and focuses on safety. Some of the features of the basic plan include:

  • Automatic crash response
  • Emergency services
  • Stolen vehicle assistance
  • Roadside assistance
  • Hands-free calling

In addition to these features, OnStar also offers a plan that includes turn-by-turn navigation services. Most of the features are free to use after you pay the monthly subscription fee, but the use of hands-free calling does require the purchase of pre-paid minutes.

How Do I Get OnStar?

OnStar is included with all new GM vehicles, and some non-GM vehicles also include it.

You may find these systems in certain Japanese and European vehicles that were manufactured between the 2002 and 2005 model years. Acura, Isuzu, and Subaru were the Japanese automakers that were party to the deal, and both Audio and Volkswagen signed on as well.

If you purchase a GM vehicle that was produced during or after the 2007 model year, it may also include a subscription to OnStar. After that model year, all new GM vehicles come with a subscription.

You can also access OnStar in non-GM vehicles by installing the OnStar FMV device. This product replaces your rear-view mirror, and it gives you access to many of the features that are available from OEM GM OnStar systems.

How Do I Use OnStar?

All of the OnStar features are available from one of two buttons. The blue button that sports the OnStar logo provides access to things like navigation and diagnostic checks, and the red button is used for emergency services. If you have pre-paid minutes, you can also press the hands-free phone button to make phone calls, access weather reports, and receive other information.

The blue OnStar button allows you to speak to a live operator at any time of day. The operator can set up turn-by-turn directions for you to any address, look up the address of a point of interest, or make changes to your account. You can also request a live diagnostic checkup, in which case the operator will pull information from your OBD-II system. If your check engine light comes on, this is a good way to determine whether the vehicle is still safe to drive.

The red emergency services button also connects you with an operator, but you will be put in touch with someone who is trained to deal with emergencies. If you need to contact the police, fire department, or request medical assistance, the emergency advisor will be able to help you.

Can OnStar Help if My Vehicle is Stolen?

OnStar has a number of features that can be of assistance in case of theft. The system can act as a tracker, which can allow the stolen vehicle to be found and recovered. However, OnStar will only provide access to this functionality after the police verify that a vehicle has been reported stolen.

Some OnStar systems can also perform other functions that might make it easier to recover a stolen vehicle.

If the police have verified that a vehicle was stolen, an OnStar representative may be able to issue a command to the OBD-II system that will slow the vehicle down. This functionality has been used during high-speed car chases to stop thieves in their tracks. Some vehicles are also equipped with the ability to remotely disable the ignition system. That means if the thief shuts your vehicle off, he won’t be able to start it back up again.

What else Can OnStar Do for Me?

Since OnStar has access to many of your vehicle's systems, there are a number of ways that an OnStar operator can help out if you're in a bind. In many cases, OnStar can unlock your vehicle if you accidentally lock your keys inside. The system may also be able to flash your lights or honk your horn if you're unable to find your vehicle in a crowded parking lot.

Some of these features can be accessed by contacting OnStar, but there is also an app that you can install on your smartphone.

The RemoteLink software only works with certain vehicles, and it's not available for all smartphones, but it can give you access to live diagnostic information, allow you to start your vehicle remotely, and also contact an OnStar advisor when you're not in your vehicle.

Are There Any Privacy Concerns With Services Like OnStar?

OnStar has access to a lot of data about your driving habits, so some people have expressed concerns about privacy issues.

The FBI has even attempted to use the system to eavesdrop on private conversations, but the Ninth Circuit Court of Appeals denied them the ability to do so. OnStar is also set up so that it makes an obvious noise whenever an operator places an incoming call, which makes it impossible for an unscrupulous operator to eavesdrop.

OnStar also claims that it anonymizes GPS data before selling it to third parties, but this remains a privacy concern. While the data may not be tied directly to your name or the VIN of your car or truck, GPS data is by its very nature not anonymous. GM also purportedly tracks this data even after you cancel your OnStar subscription, though it is possible to completely sever the data connection. More information is available from GM via the official OnStar privacy policy.