What is OBD-II?

Your car is smarter than you think. It knows how you drive, in many cases it even knows where you drive. Today’s cars are really miracles of modern technology, full of computers and diagnostic tools.

Of course it wasn’t always like this. There was a time that a qualified mechanic needed a collection of arcane tools and a keen intuition in order to understand what was going on with a car. Those days are gone, and today’s mechanics rely on computer diagnostics more than their eyes and ears. You may think that’s a move in the wrong direction, but sometimes progress doesn’t work the way you want.

In order to make it easier for computers to interface with cars, you need to have a standard interface. Otherwise, a repair shop would need a separate computer for every model of car.

It started in California

California mandated the first standard connectors for car diagnostics, and it was the first to mandated what eventually became known as On-Board Diagnostics, version 2. OBD-II started in California in 1994 and by 1996 the federal government followed suit. They required every US-made car for US sale to have the OBD-II system. By 2008 it was mandatory for nearly every vehicle. After decades of implementation, the OBD-II system is found in nearly every car in the US.

The OBD-II connector

A key part of the OBD-II system is the connector you see at the top of this article. By standardizing this connector and what the pins do, it makes it very easy to know what’s going on in your car. OBD-II shows the status of key systems and even shows the results of errors that happened in the past but aren’t happening now.

A use that no one expected

It took many years, but third-party manufacturers started using OBD-II in new ways. Some insurance companies will give you a discount if you connect a data logger to your OBD-II port. This will let the car log if an accident was your fault. Since people sometimes lie when an accident is their fault, this has the effect of lowering insurance rates.

Then, there are companies that use the OBD-II port to add features to older cars. One such system gives OnStar-like functionality, reporting problems automatically to a central server and adding Bluetooth to cars that don’t have it.

I think the coolest use of OBD-II is this Tech Choice Heads Up Vehicle Display. It uses the OBD-II system to provide real-time information on speed, fuel usage and other statistics. Other trackers do that but this one does something a little cooler. It projects that data onto your windshield. This standalone system doesn’t require a smartphone connection or Bluetooth. You connect it to the OBD-II port with the slim cable supplied and place in on the dash.

This wouldn’t be possible without OBD-II. It’s a really innovative use of a port that would otherwise be unused except for repair shops. It can turn any car into a car of the future, and of course, you’ll find this display plus other diagnostic tools right now at Solid Signal.

About the Author

Stuart Sweet
Stuart Sweet is the editor-in-chief of The Solid Signal Blog and a "master plumber" at Signal Group, LLC. He is the author of over 8,000 articles and longform tutorials including many posted here. Reach him by clicking on "Contact the Editor" at the bottom of this page.