ELM327 v2.1 USB OBD Adapter

This is a review and analysis of the ELM327 v2.1 USB OBD adapter. While it is not a ‘performance chip’, it is a tool used by automotive enthusiasts to diagnose and monitor their vehicles.  There have been MANY poor quality fakes and counterfeits from China flooding the market recently. We want to spread the word on how to identify them and prevent users from falling for these copies.  If you are looking for a REAL ELM327 v2.1 USB adapter review, then this is for you! What is this product and what does it do? Let’s take a look:



Company Profile

The manufacturer is a company called Total Car Diagnostics and they are based in New South Wales, Australia. Their website is totalcardiagnostics.com. 




The cost at the time of this review was $46.95 USD via their website. This price is average, as there are numerous ELM327 devices available with prices ranging anywhere from a few dollars to $100 or more. If you were with us for our previous ELM327 v1.5 review, that module only cost a few dollars and it did not work out too well. Our main goal was to locate a genuine ELM327 device that actually supports the commands needed to troubleshoot our vehicle. 



Product Appearance

ELM327 Totalcardiagnostics USB OBD Interface


The ELM327 module claims to interface with all OBDII compliant vehicles and protocols, and appearance-wise is very convincing. This would include most vehicles manufactured since 1996.



Internal Analysis

We purchased one of these USB ELM327 modules for analysis from the above website and looked inside:


ELM327 v2.1 Disassembled View


There are some surface mount transistors, other small components, and three surface mount ICs – one on the top side of the circuit board and two on the bottom:


ELM327 v2.1 Top Side Circuit Board Analysis View


The surface mount chip on the left side is a PIC18F25K80 chip, which is comforting, since the genuine ELM327 originally contained a PIC microprocessor. The bottom side of the circuit board has more components:


ELM327 v2.1 Bottom Side Circuit Board Analysis View


The small ic towards the top is a MCP2551 – a CAN interface transciever chip manufactured by Microchip. This is to be expected. The chip below it is a EFTDI 1702-C chip, which interfaces with the USB computer cable. So far, everything seems to suggest this may be a genuine ELM327 device. Let’s see what it does when we try to use it…



We connected the ELM327 module to our test vehicle’s OBD port and the other end to our laptop, having already installed the USB drivers and software provided. We opened a terminal program and issued a few standard ELM327 commands:


ELM327 Terminal Commands Window


We first issued the command “ATI”, which asks the ELM327 board to identify itself. It responds with ‘ELM327 v2.1’. This is a legitimate response. We issue more commands to the unit to check the response – we receive ‘OK’ as a response, so it allows us to set the protocol, etc. We issued the command “ATMA”, which tells the module to monitor all traffic on the bus and echo it to the screen. It responds with ‘OK’, meaning it accepted the command. This was not the case with the previous ELM327 device we tested. The v2.1 version seems to work and allows us to gather the information we needed from our vehicle. Most cheap copies will work to a point and provide basic data, but when the user tries to do advanced commands, they usually are not compatible, because they run a modified pirated version of the original ELM327 software, called v1.5, etc. We now know this module works well for our purposes as an automotive test tool.




It is clear from our analysis so far that the ELM327 v2.1 USB tool is a legitimate ELM327 device. Always be careful when choosing any product which connects to your vehicle!




From our research and review, it is our opinion that the ELM327 v2.1 module is a legitimate ELM327 diagnostic device. When looking for a genuine ELM327 module, look at these factors: cost, seller location and reputation, software version, etc. There are also apps available such as ‘ELM327 identifier’ to help identify counterfeit modules.





Company Communication
Power Gains
Safe for Vehicle
Total Rating



The original creators of the ELM327 ic can be found at elmelectronics.com. The ELM327 identifier app can be found at https://play.google.com/store/apps/details?id=com.applagapp.elm327identifier&hl=en

More details on the differences between the genuine and imitation modules can be found here:


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