Your Car’s OBD-II: What Is It?

OBD-II (on-board diagnostics) is a computer system that monitors vehicle systems such as the engine, fuel pumps, exhaust and much more.

When your "check engine" light comes on, it's because the OBD system has detected trouble. And when you take a car in for repairs, the mechanic typically gets system data from the OBD-II. By connecting to it with an OBD reader it can provide diagnostic trouble codes that help identify needed repairs and maintenance.

Does my car have OBD-II?

Whether you have this system depends on the model year of the car. The first generation OBD was developed in 1988 and the OBD-II was developed in 1992. Some cars manufactured between 1992 and 1995 were required to have an OBD-II. After 1996, the Environmental Protection Agency (EPA) required all cars and light vehicles (like pickups) to have OBD-II for monitoring emissions and certain engine components.

How to find an OBD-II port

The OBD-II port is commonly found on the driver's side dash just to the left under the steering wheel (locations 1 to 3, below). Other common locations include the driver's side kick panel, center console and glove compartment (locations 4 to 8, below).

Progressive has an online tool to help you find the location of the OBD-II port for your particular vehicle.

How OBD-II can help you save on auto insurance

Some car insurance companies offer usage-based insurance programs that use information on your driving habits to help determine discounts and your car insurance rate. For these programs, a telematics device connects to the OBD-II port and can record how many miles you drive, the time of day, speed, braking, when air bags are deployed and more. In newer cars with safety systems like forward collision warnings, the ODB-II will record related data.

Then with a mobile app you're able to monitor your trips with data collected from the ODB-II.

Here are some auto insurance companies that offer usage-based insurance discounts that use a telematics device with a car's OBD-II.

There are also safe-driving apps that don't use the ODB-II port, such as EverQuote's EverDrive app. These use systems in your mobile phone to track things like speed, cornering and braking.