What is a car diagnostic tool?


Check the exact pricing of Carly for your car brand.

Those who have previously tried coding know what a so-called Car Diagnostic Tool is. But the average consumer has no idea what a diagnostic tool is. We’re here to tell you what you can do with it and what you need it for.

How to use a car diagnostic tool?

A car diagnostic tool also called an OBD scanner, is, as the name suggests, a car scanner that is a diagnostic scanner for your car. OBD stands for On-Board Diagnostics. The device is connected to the car via the so-called OBD port and an OBD cable (if needed). 

The car diagnostic tool then accesses the data memory of the control units and the on-board electronics and evaluates or analyzes them. 

For this purpose, stored data from the vehicle’s electronics is evaluated, which is essential for the detection of faults. If necessary, error codes are then generated, but these must then be analyzed using the information provided on internet databases, etc. 

This is because a car code reader usually only tell you the error codes but not what it means.

The subsequent elimination of errors is possible with the help of some OBDII scan tool devices; however, this process is very complex and requires additional knowledge. Furthermore, a diagnostic device allows essential vehicle data such as fuel consumption, fluid temperatures, etc. to be readout.


In this article, we will not only show you what diagnostic tools can do, but also what mistakes you should avoid saving time, money, and effort. We also give you a broad insight into the world of diagnostic devices. Of course, we will also show you which car diagnostic tool is the cheapest and most efficient for your car and which alternatives there are to conventional diagnostic tools. 

Reasons for Using a Car Diagnostic Tool

Over time, cars have become more modern and digital. Onboard electronics are becoming more versatile and the whole car seems to be more interconnected.

Therefore more digital errors can occur, which can affect the condition and value of the car. For example, airbags may not work properly or there may be problems with the lights. Often we are not even aware of these errors.

But in the worst-case scenario, a dangerous accident can occur.  It can also happen that the life of the car is shortened by faults in the system, and repairs can cost a lot of money.

This can lead to a massive loss of value, which no car owner wants. That is why it is all the more important to invest money in a quality diagnostic device and to regularly carry out high-quality fault analysis. This can also be done by a trusted mechanic, but this is often very expensive. However, with a little bit of knowledge, commitment, and our tips you can certainly fix most of the error codes successfully.

Now you know why it’s so important to carry out regular diagnostic tests and that you can save yourself a lot of time and money. But how exactly does the diagnostic device solve our problems and save us money? Here is the answer:

After installation, the diagnostic device goes to troubleshooting. For this purpose, the OBD2 scanner device is connected to the control units and the often ultra-modern on-board electronics. These continuously store data. This data is largely unimportant and often remains unchanged. However, some of this information is essential for your diagnostic device. 

Use the car diagnostic tool at home

If an error occurs in the system or the data does not work properly, the diagnostic device reads out an error code. Now all you have to do is determine the origin of the problem. To do this, you can look on the internet or use a guide to your vehicle. With very high-quality, thus also expensive, diagnostic devices, the error is sometimes displayed directly on the diagnostic device.

With this information, you can decide whether you want to fix the error code yourself or let a professional do the job.

Anyone who wants to take matters into their own hands can usually simply delete the error codes via the diagnostic device. 

But beware! It can happen that a supposedly harmless error code has great significance for the car or that you delete all error codes right away. 

With most OBD diagnostic tools no backup is created and the step you have taken cannot be undone. This can cost you a lot of money. So if you’re not sure whether you should delete the code, or if you don’t have any clear tips on the web, you’d better head to your trusted mechanic. 

But you don’t need to worry too much about these kinds of complications, as they are rare. 

Costs of a Diagnostic Tool for your car

The price of a car diagnostic tool naturally depends on many factors. These factors include the performance of the device, the speed of the analysis, and the effectiveness of the diagnosis, i.e. how accurately a problem can be diagnosed. By performance we mean whether the device is a universal device or whether it is designed for a specific car model. Furthermore, the efficiency of troubleshooting is an important point. After all, it is important that the error codes can be reliably and cleanly deleted after an error analysis has been carried out.

In general, however, it should be mentioned that the market for diagnostic equipment has developed enormously in recent years and the range of products on offer is broad. The price range is from €20 to €5000, and the quality ranges just as widely. 

All in all we can say that you will find quality devices on the market from about 60€. And from about 100€ you can already buy high-quality devices with Bluetooth / WIFI connection.

Very high-quality and professional devices can be found from 300€ upwards and thus offer many useful options. Workshops mostly use high-tech products with a market value of several thousand Euros. 

Costs of Error Analysis in a Workshop

Error analysis and troubleshooting in the workshop is often more expensive and time-consuming than using a diagnostic device at home. 

In the workshop, simply reading out data from the control units and the on-board electronics costs about 15-30€. However, if errors are found in the system, an individual price, evaluated according to the severity of the problem, is usually charged.

Therefore, in the long run, we recommend using a diagnostic device for error analysis and then you can visit a workshop for further troubleshooting. In addition, you should also have an error analysis carried out in the workshop from time to time. 

By doing both, you can be absolutely sure that you aren’t missing any issues with your car.

Furthermore, the professionals in the workshop are often very familiar with modern troubleshooting tools and can solve most of your problems.

Alternative: Carly

Of course, there are a wide range of alternatives to conventional diagnostic devices. One of these is Carly. Carly falls into the category of coding software. But Carly is one of the few programs that also offer many other services, including error analysis, and troubleshooting. Carly also offers many other helpful features that will help you to maintain your car.

Coding BMW F30

So how can Carly help me diagnose problems?

By diagnosing with Carly, just like with conventional diagnostic devices, the most important data of your vehicle can be analyzed and evaluated. After you run a diagnosis with Carly, it will provide you with a list of error codes in the app. However, unlike most diagnostic devices, Carly also analyzes the source of the problem. Then you can decide whether you want to delete the error code or not.

But Carly also offers many other functions. With Carly you can, among other things, carry out coding on your car. You can also do a used car check with Carly. This can be useful, for example, to detect mileage manipulation when buying a used car.

All in all, the Carly program is a legitimate alternative to classic OBD diagnostic tool. And it is also worth it financially. 

For Carly you need the software and the hardware. Both can be purchased independently and the price depends on the car brand and which features you want access to.

To enjoy Carly to the fullest, only two purchases are necessary.

First is the Carly OBD adapter: The adapter part is absolutely necessary in order to use the app… Depending on where you are getting the adapter shipped to, the price can vary, for the USA the adapter is currently $79.90  in the official Carly shop.

Use of the Carly software is licensed. This means that the Carly app must be downloaded from the Apple app store or Play Store, and if you want to access the premium features, you need to purchase the annual subscription. 

Tips and Tricks

To make sure that you don’t waste any money and stay on the safe side of the law, we have researched and summarized the most important tips and tricks for you. We also advise you to always make careful changes to your car. After all, a car is a large piece of machinery and no one should put themselves in danger when using a car. 

  • See a mechanic at the right time! Of course, diagnostic devices and programs such as Carly cannot detect or correct all faults and sometimes there is simply no way around visiting the mechanic.It’s great to carry out regular tests with the device, but in case of serious problems you should go to the garage immediately!
  • Do not save money in the wrong place! In order to buy a really quality diagnostic device, you will have to spend a bit of money. There are really cheap diagnostic devices available, but we recommend to research on the internet and read a few reviews.Cheap diagnostic devices often don’t serve their purpose and you only put yourself in unnecessary danger.
  • As in most areas of life, education is the key to success. That is why we recommend that you take a good look at the subject and acquire a certain level of knowledge. This is the best way to save a lot of money and achieve the best possible results.
  • Go to the mechanic regularly! Even if your car does not have any error codes, we recommend that you have your mechanic do an error analysis at regular intervals. On the one hand, the diagnostic equipment in the workshop is often more effective and more errors can be detected, on the other hand, any error codes that arise will certainly be deleted.

Keep in mind, that every car has different software and modules built-in. Therefore specific features will vary with every model.

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