I buy a model ELM 327 OBD2 version 2.1 Bluethoot for the price of $ 3 here is the model, with a nice little note request 5 stars 
It has 16 pin like all OBD2 ports of vehicles in general and ready to work for all protocols (5 protocols for OBD2)
But in reality, this is a lie, after doing the test I see that this is nothing real.
So i decided to open the box to see the interior and what could be and I see this lean PCB
The big chip is a MCP2515, the small to be rated TJA1050 must MCP2551 (I think more TJA1050) short, a bluethoot chip BEKEN with the code inside incredible Chinese are incredible, too strong or too smart.
According to my research, the best model is indicated by version 1.5, ELM327 Version 1.5 with chip Pic18F25K80 but unfortunately even these models are different.
After much research I have found the best and most reliable of all Bluethoot OBD2 or USB or Wifi, having a PIC18F2480 chip and working with all OBD2 standards in general.
The price is much more expensive, i find for $ 15 and $ 20 without problem. If you do not make the mistake like me to inquire before you buy so you have the answer
my dad always tells me (Before doing an action, ask the opinion of the elders) and the message from Andy ( we get what we pay) we must always listen to the good advice,
thank you for reading, and wish you the best for you.
I have a cheap one I have used for years, and mostly works, with ocassional disconnects, but when looking to replace it I found mixed reviews of almost every one, so I just kept the same so far.
I don’t think every worked, but as my car is really old, I thought perhaps those features were not supported by my car
[victor_pv – Wed Apr 18, 2018 11:09 pm] –
What is the best way to identify a good one?
I have a cheap one I have used for years, and mostly works, with ocassional disconnects, but when looking to replace it I found mixed reviews of almost every one, so I just kept the same so far.
Hello dear Victor,
The best way to identify the good ELM327 OBD2 (according to research) is the one with the MAC address :
– 00: 1D : A5 : 68 : 98 : A8 (or)
– 00: 1D: A5 : 68 : 98 : 8C
All the rest with the MAC address as :
– 66: 35: 56: 78: 90: AB
– 88: 35: 56:xxx
– 00: 00: 00: 00: 00: 01
– AA: BB: CC: 11: 22: 33
– 00: 00: 00: 11: 11: 11 are very low reliability.
To find the right one must visualize the photos of the customers or the seller (I prefer the images of the customers). I just find one of this at a good price and i place an order here is the https://fr.aliexpress.com/item/Cimiva-M … autifyAB=0 .
I also order this model in reduction of -54% https://fr.aliexpress.com/wholesale?cat … canner+Elm+
with chip 18F25K80 but i regret it 
Here for me the good one, the one i go order
https://fr.aliexpress.com/item/Original … 47242.html
Sincerely.
[RogerClark – Thu Apr 19, 2018 12:05 am] –
I have one of these that looks very similar (from the outside)I don’t think every worked, but as my car is really old, I thought perhaps those features were not supported by my car
Hello dear Roger,
my car is as old (Peugeot 2.0 hdi model 2004) but the clone with chip MCP2515 has managed to find me a fault on the vehicle the sketch is in the chip bluethoot BEKEN (I think 256 ko of free memory) incredibly Chinese Bravo for the work anyway. I will keep you informed of the test results after getting the products to order.
My goal is to help his neighbor, just like you dear Roger who with your friends and help deserve a lot of Respect, I thank you for everything you do for the people of the world and your name is engraved everywhere I speak with my family of Turkey who say “Roger Clark, number 1”, thank you very much you are the good example for the youth, with my respects for you and all the team, cordially.
I my car is was also made in 2004 but its supposed to be the 2005 model 
I have read fault codes using my ELM327 and also reset them, as my car intermittently shows error codes when there is no fault.
Last time the car was serviced, they reset a code, and told me that its normal for the garage to reset the code and if the fault does not return very soon, then its just a glitch.
So I save money by resetting the codes myself.
If the fault returns I then take the car to the garage as its much easier for them to find a permanent fault rather than an intermittent fault.
That’s what most users do with the ELM327, they erase the default code to turn off the lights like the Air-bag or simile. The ELM327 real chip costs 21 € it is programmed and sold alone but has the advantage of being the original OBD2 project.
Otherwise there is also the shield with the most similar chip ELM327 is the STN1110 which costs quite expensive. Another Arduino shield Can Bus a bit cheaper is the one with the chip MCP2515 and TJA1050 towards D-sub, it costs in the 7 to 10 €.
Personally being amateur i will just use those already ready to use. A good STM32-OBDuino full protocol project would be ideal but would require a lot of work and knowledge, in short for now it looks cool to try its small devices quite useful if reliable.
Very good weekend for everyone, best regards
STM32 has CAN bus support, but it conflicts with the USB on the Blue Pill, hence its not implemented in my Core.
Though some people made it work and use an external USB serial adaptor
[RogerClark – Fri Apr 20, 2018 11:01 am] –
Some people are working on car computers, some use CAN / OBD but I don’t think anyone has written software specifically to act like a OBD e.g. read fault codesSTM32 has CAN bus support, but it conflicts with the USB on the Blue Pill, hence its not implemented in my Core.
Though some people made it work and use an external USB serial adaptor
Thank you very much Roger for the information,
currently i saw projects of communication CAN BUS with Arduino and the small module MCP2515 for the vehicles conforms to OBD2 standards (16pin). I order one of these to make a trial, i will keep you informed of the result obtained, thanks again,
cordially.
I had to check them!
[zoomx – Fri Apr 20, 2018 6:37 pm] –
I have two of them, my car is an old Opel and they doesn’t work, bluetooth is ok but nothing from the engine.
I had to check them!
Hi, zoomx,
from what i can understand, the opel uses the K-Line protocol.
https://forum.arduino.cc/index.php?topic=486856.0
Here is an interesting project for Opel. A brave young man shares his project with an instructive explanation
http://blog.workingsi.com/2010/10/resea … rface.html
Sincerely.
- 20180421_095810_IMG_0879_b.jpg (45.68 KiB) Viewed 916 times
- 20180421_100631_IMG_0891_b.jpg (42.92 KiB) Viewed 916 times
The first seems to be similar to mine, the main chip BEKEN works for the bluethoot and houses the code in its memory, the small chip NCV7342 is for the CAN BUS, according to what i saw, the reliability remain limited.
The second is more interesting and has the correct basic chip but it should identify the outputs, here is an image that looks like your OBD2, the K-line interface is show, i think you also have this output but not the same values of resistance? I am too amateur to be precise, to forgive my poor acquaintance.
The ideal would be to realize a complete project STM32 full protocol with a good code but i am too null for that, if i find interesting projects i will try to realize one and would share the result, cordially.
http://science.donntu.edu.ua/ks/novikov/library/
use google translate to translate them
https://translate.google.com/translate? … t=&act=url
[ag123 – Sun Apr 22, 2018 5:42 am] –
on the topic of ODB2 did some google and run into this site, apparently a Russian/Ukraine site,
http://science.donntu.edu.ua/ks/novikov/library/
use google translate to translate them
https://translate.google.com/translate? … t=&act=url
Hello ag123, thank you very much for your sharing, it’s a pretty complete page on OBD2 to understand the operation, I’ll read, Thank you again, it’s nice, cordially.
and it didn’t take too long googling before i run into this
https://github.com/stanleyhuangyc/ArduinoOBD
https://freematics.com/pages/products/a … d-adapter/
https://freematics.com/pages/products/a … ics-kit-3/
apparently freematics is building an Arduino OBD2 scanner
this is an interesting development as after all elm327, elm323 is getting ‘somewhat basic’ compared to the capabilities of mcu’s these days.
as it goes an arduino odb2 scanner in addition to interfacing the ecu would be able to *log the sensors* while the car is running, just that i’m not too sure how safe would that be to interface the ecu on a running car.
i’d guess it’d be quite feasible to port that to stm32 blue pills / maple mini, for some of the interface the bit rates are ‘too easy’ for stm32 e.g. 10kbps
as the voltages for odb2 is rather high e.g. 12v my guess is that it may take using some interfacing transistors e.g. uln2003 with pull up resistors to interface those higher voltage circuits on odb2
Thank you again for sharing, in fact i already saw this project but as the price of the adapter was $ 45 and especially my amateurism about the OBD2 and protocols had cooled down. The first share link is beautiful to understand how the OBD2 and its protocols work.
What would be very interesting and useful would be to make a full OBD2 that could read the errors and erase the defects after repair of the vehicle while keeping the device for other vehicles acquired in the future. Interesting and inexpensive projects to find on the net are usually for only 1 protocol and this remains limited.
There are also examples with the OBD2 USB which can be added an arduino and an LCD screen to have the indications directly on the screen control by arduino … in short interesting subject because unfortunately the scams are frequent at the garage or by buying a vehicle …
The ideal would be to have a full protocol tool so for example scan the vehicle before purchase to be sure of the seller or before bringing it to the garage … Thank you very much for your contributions, with my respects for you all,
cordially.
Here are the results of the test model ATDIAG MINI OBD2 version 2.1 received.
The mini bluetooth uses the right MAC 00: 1D: A5: 68: 98: 8A address and pretends to work with all versions, the theory is OK but in practice this adapter does not read all the fault codes … as indicated by the theory.
So i guess the software part is just getting around but how ?
I am too amateur to be precise. The chip is not visible unfortunately.
After research of the models mini bluetooth correct, the one that would be the most suitable would be the model 2 floors with chip PIC18F25K80 and Bluetooth module,
Cordially.
I never used an app to identify the version: is there a way to turn on the adapter without inserting in the car?
I burn the first fake adapter with chip MCP2515 wanting to try at home the error that i made was to use the pin ttl of the pcb, i should have directly use the 16 pins OBD2.
The number 16 is + 12V (minimum 9V), the numbers 4 and 5 are welded together the 4 is the chassis (chassis ground) and the 5 is the signal ground (signal ground).
With ELM identify or other (free) applications like ObdMax is good too.
Cordially.
which means that in reality it is marketing to make fans like me believe that this is a good deal after opening the box to see the PCB, i quickly understood the little game seller
good finally this adapter OBD2 works better than previous.
I think it’s worth it without being a bargain. It has the 18F25K80 chip and a CAN chip “tja?” 1050, BEKEN BK3231S bluetooth chip, 5V 78L05 and 3.3V AMS1117, crystal 4000 (good according to users).
For the tests, it is more efficient, reads more probes, gives more information but remains limited. I’m waiting for the 4th OBD2 (mini bluetooth) i think it would be the same as the ATDIAG
Finally after all the research, shopping “cheap” and tests, i think the ideal would be the one with the chip PIC18F2480 or PIC18F2580 with MCP2551, LM317 and LM393 which would be the most complete OBD2 clones, the one with 18F2480 chip automatically has all the necessary.
A tip is that in general its adapters have visible light LEDs, we can see the colors of the leds from outside the OBD2 boxes, the boxes with LEDs like the one present are not very good. the last 3 photos show the ideal OBD2 (from $ 15).
Here i am happy to share this adventure and i hope to facilitate the search for future customers good OBD2 adapter
Regards.
http://club.dx.com/forums/forums.dx/threadid.465601
Thus, the Chinese and ELM327 will be happy to sell their products the OBD2 adapter 15 € + the chip ELM327L for 21 € = 36 € (I do not know if ELM327 do pay shipping costs, which should be added in this case). Happy workers day, best regards.
Today i tested the clone model with PIC18F25K80 and a free application (DashCommand) using an android samsung, i was quite astounded by the display of several probes in real time.
From the simple speedometer to fuel consumption and a lot of other useful info that i did not understand, my old Peugeot was a formula1
What surprised me especially it was the mini blue clone with the so-called invisible chip version 2.1 by the vendor who is visible as version 1.5 on the test software and has a good MAC address 00: 1D: A5: 68: 98: 8B. It worked almost like the PIC18F RPM in real time, engine temperature, air pressure … incredible but it is not as stable as the PIC18F.
According to long research and i’m not 100% sure it says that this little hidden chip could be the STM32F042. If so, they may have simply injected the cloned version v1.0 code with improved firmware (Shenzen mode). It is impossible for me to find accurate information on clones because in China, whoever opens a factory can manufacture what he wants (+/-).
Some sell versions that do not exist at ELM (Canada) “I would like to take this opportunity to say, respect to the developer of ELM (Canada) i would like to buy a chip ELM327 with new firmware 2.2 out of respect to the project developer,
if i can only replace the PIC18F2480 clone chip without touching the other components by the ELM327MS.
Otherwise it is even possible to realized it with the old with PCB to hole and wires everywhere and the ELM327L i saw version 1.3 a or b for $ 17 at ELM, the 1.4 is out of stock and is no longer produced (+ 8 $ postage) During my research i also came across a scanner obd2 the CR3001 sold at this moment to 19 .xx $ instead of $ 25
But after seeing a disassembly of one of its obd2 scanner that had a main chip GDM32 (Like STM32?) and lm393 and lm317 with MCP2551 very similar to the components of the circuit ELM327 which my separated from this interesting model is the lack of tutorials, the price is affordable, lcd screen and features similar to OBD2 adapters but i prefer OBD2 ELM327.
It is easily possible to add CanHS and CanMS mode for Ford …. using a 6-pin ON / OFF / ON switch, to switch mode according to OBD2 protocol of the vehicle. There are also rules to respect when we erase a code, it is important not to touch the controls, speed levers … during the erasure.
To finish, personally i think that all the clones revolves around the version v1.0 cloned, the firmware changes are built, surely to improve the bugs of the v1.0 version. The Chinese are strong but not correct, they should finance the director because thanks to ELM327, many Manufacturers of components sell this model so we do not understand who is what, it is the version … 1.4 – 1.5 – 1.5a – 2.1 …
Which does not exist at ELM (Canada). There is a model that i like very much, this is the model ELM327 v1.5a metal models vary, some are cut with orange leds, the one i like is a model very similar to the original circuit editing, has the chip 18F2480 voltage regulator … USB mode (FTDI) not RS232 as the original but it is addable (already seen a tutorial).
On the metal box it is written ver1.5a (does not exist at ELM) inside the PCB it is indicated v1.2 can be that the metal box gave it the v0.3 to become 1.5a: ) but the editing is good enough, it lacks a filter in comparison with his little plastic brother
Conclusion: there are compatible models like elm327 OBD2 bafX and other similar and reliable brands compared to other clones but looking at the PCB they are similar to the images above, can be the firmware is more improved or can be only blah blah to sell.
I will order the 18F2480 these are the best and most reliable for me. If the seller does not show the PCB on the image of the ad do not buy, the models like 2.1 or the pretty stickers are not reliable because one can fall into the same trap as me with my OBD2 without PIC chip nor even STM32 but a simple MCP2515 I wish you the best OBD2 for you,
cordially.
To finish this subject i would like to share my results of my research. The ELM327 is not a really complete tool, it’s a generic, it’s good to use it to see faults (only accessible faults) and you can also view some live probes like (RPM, Current speed, Air pressure ..). 
Apart from clearing the flaws we are very limited to perform more advanced operations such as accessing the Air-Bag and ABS calculators. To make readings and writing more complete it is said to use the cable and software for each model.
Example :
for Renault requires the cable CAN-CLIP,
for Peugeot / Citroen PSA requires a cable Diagbox PP2000
for WV AUDI SKODA SEAT the VCDS cable (formerly called VAG-COM)
for OPEL requires the Op-COM cable … 
But there are also Multi-Diagnostic cables like the Delphi DS-150e with all OBD sockets for different brands and protocols, the Autocom CDP +, the 2 are identical and can use the software like WOW – WURTH – DELPHI – AUTOCOM, like to use at the garages of professional automobile. Here is the information in general that i obtained after research.
I wish you vehicles without problem,
cordially.
It was a long time, i was often passing to read your messages but not attend for lack of knowledge to provide an answer. The car has taken me all the time empty, now i know better the diagnosis of vehicles.
I am ready to help with adapters and software for each group of vehicle brand. Unfortunately the Elm327 and its software such as android or pc are not complete because of the weak components on the Elm327,
but there are still powerful software like Forscan for Ford which is good or for DDT4ALL for Renault, very powerful and even dangerous in CAN mode, FNR4In1 key coding for RN, FRD … provided you have the proper cable biensur with PIC18F2480 or 25K80.
The software uses an EL327 to program or register a new key. In short the world of the automobile is too vast, all roads lead to STM32duino.
Respect to all the team.
