We are often asked questions regarding code readers, scanners and diagnostic tools.
There are a massive range of devices out there and it can be daunting as to what is the best choice.
We will attempt to answer some common questions and give some advice on what might be best for you.
What's the difference between a code reader and a scanner?
Both of these are colloquial terms, and are used somewhat interchangeably. Typically a "code reader" might refer to a more basic machine and a "scanner" might be more advanced. Neither of these are really an industry term or have a specific technical definition.
Basic generic OBD2 readers available for somewhere around £50GBP ($70USD) or less will usually give you codes relating to engine issues, but won't give information relating to all the other systems of the car.
Advanced diagnostic tools for workshop use (frequently around £5000GBP/$7000USD) will often allow you to interrogate, diagnose and reprogram most modules within most vehicles.
Say for example an error for Active cruise control has shown up on your new Mercedes, an advanced unit will highlight that its a failure in the front radar unit, then allow you to program and calibrate the replacement part after fitting it to the vehicle.
There are thousands of devices that fall somewhere between these price points, that offer different levels of functionality. Some might cover a lot of depth on a single vehicle (great if you only have one car), some might cover a wide range of vehicles but give more general information.
There are a wide range of very cheap devices that when paired with a smartphone app can give a good level of information.
Devices like the VGate i-Car dongle are around £15 and can pair with an Android or iPhone.
What doesn't it do?
Probably the most important point here is that no diagnostic tool at any level replaces the knowledge of a good mechanic, automotive engineer or enthusiastic hobbyist.
A code reader, scanner or diagnostic tool does not point out the exact part that has failed, but more the area in which you should investigate.
Just as an example, your scan tool may show "P0234 OBD-II Trouble Code: Engine Overboost Condition". The reaction of many hobbyists (and actually many mechanics) is to replace the boost pressure sensor.
Most commonly in my experience the boost pressure sensor is unlikely to be the cause of this issue, merely the symptom. Often sticking turbocharger vanes on Diesel vehicles will be the issue here, which can often just require cleaning.
What are the benefits of owning and using one?
Any code reader gives you a huge advantage, even the simplest code reader will give the user valuable information. Even if the only use is to give the codes to your mechanic at the roadside, they can advise as to whether it is likely a minor issue or whether you should have the car recovered to a workshop.
More advanced users might be able to use an app to log live data from their car, which could help to diagnose issues, or to help a hobbyist tune or otherwise improve their car.
What are the best places to research codes and why?
Technical definitions of codes are extremely easy to find. What is more helpful is finding help to diagnose an issue based upon those codes.
Car forums and social media groups dedicated to your specific vehicle are very helpful for this. Again it is important to bear in mind that not everyone here is an expert, but often car groups can help you to find the cause of a problem yourself.
This could help you to repair a fault yourself, or it could just give you enough background to understand what needs to be done, and what others have been charged for the same job.
In summary:
If you aren't sure where to start, a simple wifi OBD dongle and smartphone app is a great place to start. You will struggle not to get good value from one of these.
Even if the only thing you ever use it for is to display some cool looking gauges on your phone, or look up some live data from your perfectly working car, that's still interesting for most enthusiasts.
At some point it is very likely to have a good practical use in reading a fault code, and even just a little bit of peace of mind as to what's behind that glowing engine management light is worthwhile.
