How To Use An OBD2 Scanner

One of the major benefits of working on modern cars is the ability to diagnose problems by reading error codes with a diagnostic tool. They are plug and play devices and within this article, we show you exactly how to use an OBD2 scanner.

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How To Use OBD2 Scanner
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Although there are more things to go wrong with modern cars, their issues are easy to pinpoint when using an OBD2 scanner. Whether you use a budget or premium diagnostic tool, both will be able to provide error codes such as the above vehicle that currently has DPF problems. Learning how to use an OBD2 scanner yourself can save you a fortune in the long run because most garages will charge between £20 to £50 to just read the car’s codes.

At 4Car, we are lucky enough to own many of the best rated OBD2 scanners and have put together this guide on how to use the devices. As long as your car features an OBD2 port, you can use pretty much any OBD2 scan tool.

Locating The OBD2 Port

Before you begin to use an OBD2 scanner, you must locate the port to plug in the scanner. In the majority of cars, the OBD2 port is located beneath the steering wheel but it can also be located in the glove box or armrest.

If you have looked under the steering wheel and can’t see anything, it’s important to note that some may have a cover protecting the port. You will therefore need to remove this cover in order to gain access to the port.

The below photo is an example of the OBD2 port underneath the steering wheel and it’s a standardized design, which means the port looks identical regardless to the car you drive.

OBD2 Port

Older Cars Without An OBD2 Port

If you drive an older car that doesn’t feature an OBD2 port, there may be some diagnostic tools available. For example, we own multiple classic Mercedes’s and you are able to use the brand’s dedicated STAR system. Alternatively, you may wish to use a more affordable probe device that many brands offer for older vehicles.

How To Use An OBD2 Scanner

  1. Plug in the scanner into the OBD2 port.
  2. Turn on the car’s ignition.
  3. Power up the scanner.
  4. Select “scan” (or the equivalent depending upon the scanner).
  5. Write down any codes that were found.
  6. Clear any stored error codes.
  7. Repeat the scan process to see if the codes remains.

All OBD2 scanners are different but the above steps are the “basics” in terms of how to use an OBD2 scanner. For example, some scanners use Bluetooth to connect the OBD2 device to your phone whereas others are a standalone tool that’s powered by the car’s ignition. For most people, the hardest part of using an OBD2 scanner is locating the OBD2 port in the first place. Of course, if you wanted to do a bit more than diagnose codes, more advanced tools offer a whole host of features such as customisation, actuation and so much more.

How To Use Car Diagnostic Tool

Other OBD2 Uses

As well as plugging in an OBD2 scanner, you can also use the OBD2 port for other devices too. For example, if you wish to use an aftermarket HUD, this can be achieved by the device retrieving information from the OBD2 port. Other examples of aftermarket use of the OBD2 port include using it for tracking your car.

Many car manufacturers also use the OBD2 port to retrieve driving data from the factory. As you can see in the below photo, our MK7 Volkswagen Golf has a factory fitted OBD2 device fitted that passes data to the car’s head unit. This data can then be shown via the “Driving Data” tab upon the head unit. Some of the latest double din head units also offer this type of functionality too if you wish to add it as a modification to your car.

how to use obd2 bluetooth scanner


The ability to use an OBD2 scanner is crucial in terms of diagnosing issues with your car. As mentioned above, we own multiple (as shown below) and its one of our most used tools in the garage when working on cars. Rather than relying on guesswork, we can pinpoint any issues and determine any parts and components to strip down.

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author dan 4car

Written By Dan

Dan has been a car enthusiast ever since he can remember and has an extensive range of cars that include classic cars that he has restored himself from a barn find condition to modern performance cars. Whether you need advice on how to install car parts or recommendations on what products to buy, Dan’s first-hand experience will certainly help.

If you want to find out more about Dan, our testing process or the website itself, visit our about page for further information.

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