How Does GM's OnStar Service Work?

OnStar is a subsidiary corporation of General Motors that provides various in-vehicle services; all delivered using a CDMA cellular connection. It's also the name of a service that's available in new GM-family vehicles.

What's Available With OnStar

Some services available through the OnStar system include turn-by-turn navigation instructions, automatic crash response, and roadside assistance. You can access these features 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 made the first OnStar units in several Cadillac models for the 1997 model year.

OnStar is primarily available in GM vehicles, but a licensing agreement also made OnStar available in several other makes between 2002 and 2005. GM also released a standalone unit in 2012, which provides access to some of the OnStar services.

How Does OnStar Work?

Each OnStar system that's installed as original equipment can gather data from both the onboard 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, you will incur additional costs for hands-free calling.

OnStar can transmit GPS data using the CDMA connection to the central OnStar system to provide turn-by-turn directions. They can also use the same GPS data for emergency services functionality, allowing OnStar to summon help in an accident.

OnStar can transmit data from the OBD-II system. This feature can allow OnStar to track your mileage for insurance purposes, provide you with vehicle health reports, or determine if you've been in an accident. Since you may find yourself unable to reach your cellphone after a serious accident, the OBD-II system notifies the OnStar call center when it determines that your airbags have gone off. You may then request help if it's needed.

What Are the Available Features?

OnStar requires a subscription for it to work, and there are four plans available. The Connected Vehicle plan, which is the least expensive, omits many of the features available in the more expensive plans.

Some features of the Connected Vehicle plan include:

• Advanced diagnostics
• Vehicle locate
• Remote access

For comparison, the Premium plan, which is the highest plan you can get, includes all the Connected Vehicle features plus:

• Automatic crash response
• Emergency services
• Crisis assist
• Roadside assistance
• OnStar Guardian app
• Stolen vehicle assistance
• Turn-by-turn navigation

Some features are available as an add-on and so do not come with the plan. See the OnStar Plans and Pricing page for detailed information on these plans, including all the features and pricing options.

How Do I Get OnStar?

GM includes OnStar with all new vehicles, and some non-GM vehicles also include it. You may find these systems in certain Japanese and European vehicles manufactured between the 2002 and 2005 model years. Acura, Isuzu, and Subaru were the Japanese automakers that were part of the deal, and both Audi and Volkswagen signed on as well.

If you purchase a GM vehicle 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 available from OEM GM OnStar systems.

How Do I Use OnStar?

All the OnStar features are available from one of two buttons. The blue button that sports the OnStar logo provides access to navigation and diagnostic checks, and the red button is used for emergency services. If you have prepaid 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, and you will be put in touch with someone 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 several features that can be of assistance in case of theft. The system can act like a tracker, allowing the stolen vehicle to be found and recovered. However, OnStar only provides 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 issue a command to the OBD-II system that slows down the vehicle.

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 disable the ignition system remotely. That means if the thief shuts your vehicle off, they 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 many ways that an OnStar operator can help if you're in a bind. Most times, OnStar can unlock your car if you accidentally lock your keys inside. The system may also flash the lights or honk the horn if you cannot find your vehicle in a crowded parking lot.

You can access some of these features by contacting OnStar, but there's also an app you can install on your smartphone. The RemoteLink software only works with certain vehicles, and it's not available on all smartphones. Still, it can give you access to live diagnostic information, allow you to start your car remotely, and 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 privacy concerns. 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. GM also set up OnStar to make a noticeable noise whenever an operator places an incoming call, making it impossible for an unscrupulous operator to eavesdrop.

OnStar also claims that it anonymizes GPS data before selling it to third parties, but this practice 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 nature, not anonymous.

GM also purportedly tracks this data even after canceling your OnStar subscription, though it is possible to sever the data connection completely. More information is available from GM via the official OnStar privacy policy.