What is the j2534 tool? Which is the best?


J2534 tool was born to solve the difficulties of garages in finding tools to analyze and reprogram the car’s ECU. Do you know what are the advantages of J2534 and which J2534 devices are most commonly used? Let’s find out with Eurocartool in the article below!

What is the J2534 tool?

J2534 is the name of a computer-to-vehicle connection protocol. It was designed by the SAE (Society of Automotive Engineers) and authorized by US EPA  (Environmental Protection Agency).

The purpose of this protocol is to create an API (Application Programming Interface), that will be adopted by all vehicle manufacturers, allowing the user to have the ability to program the ECU without the need for specialized tools. From there, you can perform programming of the ECU control box, and even diagnose the vehicle with full features like using a specialized device of the company.

J2534 cable is a piece of hardware that helps to communicate between the computer and the vehicle. Its task is to receive, transmit and translate information back and forth between the computer and the ECU control box into a J2534 standard protocol that both the ECU and the computer (specifically the software on the computer) understand.

Why J2534 Cable was born?

Vehicles are becoming more and more complex and almost every function is controlled by the Electronic Control Unit (ECU). When the ECU fails, the mechanical components also have problems that make the vehicle unable to function properly. Then the replacement of defective parts will be ineffective and very expensive. In essence, the software in the control box really needs to be fixed by reading and clearing the error.


However, to be able to read the ECU, you will need to have protocols compatible with the control box to be able to share data back and forth. At this time, each vehicle manufacturer has its own tool for analyzing and programming their products, and this tool is often very expensive. This makes it difficult for a car, bus or truck workshop to analyze and repair all types of vehicles.

Therefore J2534 cable was created to deal with common vehicle problems such as:

  • Improve vehicle performance
  • Increase power and reduce fuel consumption
  • Some error codes appear, the only way to fix it is just to update the software
  • In addition, updating the software of the control box also helps the mechanical parts work more smoothly, helping to increase the durability of the details in the system (the picture below is the process of updating the software for the box). control ECU on Kia Carnival car)

Basic features of J2534 Passthru

The J2534 hardware acts as a connection port between the vehicle’s ECU and the PC. This relay translates messages sent from the PC into messages of the protocol being used in the vehicle’s ECU. J2534 supports most of today’s connection protocols such as:

  • ISO9141
  • ISO14230 (KWP2000)
  • J1850
  • CAN (ISO11898)
  • ISO15765
  • SAE J2610
  • J1939 (since 2005)

About the form of connection between the computer and the car: J2534 can be connected by RS232, USB or via Bluetooth, Wifi…

Normally, a J2534 tool will have the shape of an OBD II jack, in case the car’s diagnostic jack is not OBD II standard, we must know what information about each pin on the diagnostic jack is to be able to extract it. manual connection wire

The maximum length of the J2534 device is 5 meters, if it is longer, it will not guarantee data transmission. The J2534 device requires sufficient 4Kb buffer memory in transmitting and receiving data. And the processor chip must be fast enough to process all the information without being missed

Some popular J2534 devices

On the market today there are many types of j2534 tool, but below Eurocartool will list a few of the most commonly used devices, including:

  • VCM II: is a fault reading device for Ford and Mazda. Connected to the vehicle through the OBD 2 port and operated on the specialized software IDS for FORD – MAZDA.
  • Toyota Mini VCI Cable: is a high performance diagnostic and programming connection cable, compatible with SAE J2534 (Pass-Thru), providing professional fault diagnosis for Toyota / Scion / Lexus models 2000-2016 model with the function of Reading and clearing engine error codes, ABS, SRS, ETC, Main body system ….
  • VCXDag: is a device designed according to SAE-J2534 (Pass-Thru) standard, it works connected to a computer via USB 2.0 and Bluetooth. VCX Nano is widely used in the world.
  • Autel MaxiFlash Pro: provides advanced programming functions for today’s car models and manufacturers at an affordable price.
  • SVCI J2534 STIC
  • VNCI J2434

There are also many j2534 tool on the market today.

Above is detailed information about J2534 tool shared by Eurocartool technicians. If you have difficulty using or need advice on choosing the right J2534 device, please contact us via WhatsApp: +13155472355

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