I believe the J2534 adapters are the future of car diagnostic tools for home mechanics as they can give you professional OBD-II functionality for a cheap entry price. I bought and compared 5 of them, ranking them from best to worst in the following table.
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xTool A30

Topdon Topscan Lite

Thinkdiag2

Kingbolen Ediag

KDiag
Who tested product & wrote this review?

Tester & Editor for this review: Juraj Lukacko
Hello, I am Juraj (Yuri) and I tested this product to help you decide if it is something you would want to buy, and if yes, show you how to use it.
I make honest reviews based on personal testing in my own garage and If I see the product is bad, I will make it very clear in review.
Read more about how I do reviews on Iamcarhacker.com in my review policy.
xTool A30 is an ultimate budget pick

xTool A30 is a Bi-directional scanner with decent vehicle coverage for its price. The best part of this scanner for us DIY mechanics is that updates are free for a lifetime.
So you only pay once and you get to enjoy this tool for as long as it works without having to pay a yearly license.
It does everything you need to diagnose car problems and even used car checks.
Let’s stick to exploring cheaper options first and then we will work our way to more expensive scanners.
Konwei KDiag

Konwei Kdiag is a scanner I discovered just a few months ago when someone pointed it out in YouTube comments on my channel as a great budget pick.
It can scan all modules, do bi-directional testing, and even perform some service procedures like oil reset, brake pad reset, etc… a total of 4 procedures.
It does not have a large brand coverage so I suggest you download the app KDiag first and check if the brands are a good fit for your needs.
Adapters comparison
Let’s compare these scanners’ features to help you make decisions based on key parameters.
xTool A30 | Thinkdiag2 | Driverscan | Topscan Lite | |
Full scan | Yes | Yes | Yes | Yes |
Full live data + graphs | Yes | Yes | Yes | Yes |
Data logging | Yes | Yes | Yes | Yes (+ photos) |
Diagnostic report | Yes | Yes | Yes | Yes |
Bi-Directional | Yes | Yes | Yes | Yes |
Service procedures | 8 (cheapest version) | 15 | 15 | 8 |
ECU coding | – | Yes | – | – |
Subscription price (year) | FREE | $95 | $50 | $50 |
Adapter price | https://amzn.to/4eIO3IE | https://amzn.to/4eIO3IE | https://amzn.to/4eIO3IE | https://amzn.to/4eIO3IE |

Hi, I am Juraj “Yuri” Lukacko. I got frustrated by unhelpful and scammy mechanics, so I decided to learn everything about car diagnostics myself. I test dozens of new car diagnostic tools every month along with learning new strategies to fix and customize cars. About Juraj Lukacko (Yuri)