OBD2 Reader

Like having your own mechanic!

The term will be familiar to most of you. But do you really know what an OBD reader is responsible for or what you can do with it? We will delve into these questions today.

So, what is an OBD reader? OBD stands for on-board diagnostics, and an OBD reader is a vehicle diagnostic device that can be used to read the data that is recorded while driving your car. The data collection initiates as soon as you start the engine. 

Thus, the OBD connector serves as an interface between the ECUs and makes it possible to delete bad error codes. But you should only do this if you also know what you are doing. Otherwise, this can lead to serious problems with the car. These error codes can be loaded onto your laptop, tablet, or smartphone with the necessary software or app.

Now that you have an overview of what such an OBD device is, we will now show you what you can do with it and how it can help you to keep your car in better shape.

What can be read with an OBD reader?

A lot of data can be read out with an OBD reader. 

For example, once you’re parked you can read the exhaust gas values recorded while you were driving — therefore seeing how the car behaves. However, both the reader and the software or app you use are important. 

If you have a faulty reader or don’t have an appropriate program for your car, the best software on the market won’t help you. Every OBD reader manufacturer has their own device to plug into the car and usually a corresponding app or software to make these error codes visible. 

Therefore, the reading of the codes will vary widely from one company to another.

However, it can be said that exhaust gas values, torque, fuel consumption, etc., can be read out with pretty much any diagnostic software. But there are also vendors that allow you to do a used car check or analyze the health status of your car, for example. 

Professional car mechanic working in a service station.

Professional car mechanic working in a service station.


Carly is an app that allows you to get a lot out of your car for little money by reading out the data transferred with their OBD reader. 

And in many ways, Carly’s OBD reader  is unlike other diagnostic devices. The Carly Universal Adapter is a one-time investment of €59.90. You can then purchase the appropriate app in the app/play store, or use the free version if you only need access to certain features. 

If you want additional features, upgrading to the full app costs between €21 and €80 yearly depending on the car brand that you would like to use Carly for. 

There is also a version that allows you to work with all car brands supported by Carly, which is called “All Brands”.

 Carly is much more affordable than the kind of diagnostic device that you can find in a professional workshop, which costs a few thousand euros. However, it gives you access to much of the same information and features. 

Code your car with an app!

Inspect your car with an app!

With Carly you can carry out a used car check, as mentioned at the beginning. This is available for BMW, VAG, Mercedes, Renault/Dacia, and Porsche models. 

This feature is always helpful if you want to buy a new car and want to check more than just the obvious things. With Carly you can really look under the hood and get a better feeling for the condition of the car, avoiding negative surprises. 

Carly is also quite helpful if you want to make changes to your car, because it gives you the chance to do all sorts of coding on BMW, VAG, and Toyota/Lexus models yourself in the comfort of your garage. With Carly, time-consuming (and expensive) workshop visits are a thing of the past. 


What does reading out error memory mean?

The fault memory is present in every modern vehicle and is responsible for storing technical defects or faults. By then reading them out with an OBD reader you can often then correct the errors. A common misconception is that all error codes are bad. 

However, it is quite normal that cars have error codes. Which codes vary from manufacturer to manufacturer, but having some is quite normal. Only a handful of  error codes can lead to serious complications.

It’s also useful to know that there are both static and sporadic error codes. The latter are automatically deleted after a certain number of driving cycles, unless they have recurred.


How can I read error codes?

Error codes can be read using an OBD reader.. However, for these to become visible, you must have diagnostic software installed on your laptop or smartphone. The error codes will then be displayed on your screen and you will be able to make corresponding changes. 

Keep in mind that you can only read your car with the reader if it was built in 2001 or later (gas/petrol) or 2004 or later (diesel). To read older BMWs and occasionally VAGs (from 1996 on), you need the Carly reader and a special extension. If you have questions about this, you can easily contact their customer support and they will gladly inform you about which extension you need. 

When you go to connect to your car with a laptop, you need the right diagnostic  software and an reader. With your phone, it’s easier and faster to connect. You also need  a diagnostic app, such as Carly, and their universal reader that works with all brands. You can check the brands supported by Carly in the website www.mycarly.com


Where is the OBD interface located?

The OBD interface is usually located under the steering wheel, but this varies from manufacturer to manufacturer. In older vehicles, the interface can also be in the trunk or near the handbrake. Once you have found the access port, you can easily plug the reader in and the connection between the car and the diagnostic device is established. 

After that, the error memory can be read out and the different error codes will be displayed on your screen. Normally, the error codes are displayed in a code that can only be deciphered after an internet search,  which will cost you a lot of time, and you have to decide which information to trust.  With Carly, you’ll immediately see what’s wrong and you don’t have to spend hours searching on the internet.

What is the difference between OBD and OBD2?

OBD2 is used in newer cars and was introduced in Europe in 2001 and 2004 respectively in order to have a uniform system for cars. In principle, it has the same purpose: it serves as an interface between the ECUs and the diagnostic device. However, there is a big difference. 

Previously, only certain diagnostic devices could access certain cars, for example, an OBD reader from BMW only worked with BMWs, because each car brand had a different connection. This made it difficult for workshops to make diagnoses for several car brands.

In the USA, the OBD2 connector was actually introduced in 1996 to standardize the system. That’s why you’ll find an OBD2 plug for cars from America built after 1996, while a 1996 car from Germany will still have an OBD plug.


Can I diagnose all cars with an OBD reader?

With an OBD reader it is only possible to diagnose certain car brands, since each car brand has its own individual plug. As mentioned earlier, if the car is a gasoline engine and was built in 2001 or later (in Europe), it has an OBD2 plug. Diesel cars started requiring OBD2 in 2004.

With OBD you can only read the cars, if  you also have the right reader for. For example, if you have an reader with which you can read BMWs, you can only use it on BMWs built before 2001 or 2004. For Renault, you would need a different reader.

This is also the reason why a uniform system has been introduced. This makes it much easier for workshops to repair different car brands without spending a lot of money on readers. 

Carly is a user-friendly reader and can be used with all brands and models from 2001 onwards. So, for example, if you have a BMW and a VW in your garage that were built after 2001 and 2004 respectively, you only need one reader instead of two. 

So you save money and also a lot of research work, because every plug at OBD is different.

OBD3 – reality or a pipe dream?

Currently, if your OBD reader detects error codes in your car, you will see a warning or a light on your dashboard. However, you can still decide for yourself if and when you will have the part replaced. At the latest, a mechanic will check on it during your next scheduled workshop visit, so you might decide to not make a separate trip.

With OBD3, deciding to wait would no longer be possible. Because when an error code is detected, a notification would automatically be sent to the competent authority, which would then give you a deadline for replacing the defective part. If you do not meet the deadline, you would be liable for a fine. 

Bypassing the system would not be possible because the error code wouldn’t go away until you replace or repair it.

The United States is already a few steps ahead of Europe here. OBD3 could be used there as early as in the next few years. Whether or not it will be implemented in Europe at some point is unclear.

OBD2 Reader

Like having your own mechanic!