ELM327 & Class 2 Serial Data

[AmpOverload]

I believe there is a message running on the network since the instrument cluster has the coolant temperature gauge.

Then you should see a "49 10 10" somewhere in your scans, assuming they cover a long-enough time period. (Things like ECT and transmission fluid temperature will not be seen very often since they obviously don't change as fast as something like engine speed.)

Where can I find the detailed info on all of the bytes of the serial commands? I found this website but it is not so detailed (or I don't understand this info enough).

That website you linked to is a good starting place, but your question is too vague to answer. There are way too many cases of "serial commands" to give you a sensible, succinct reply. Are you interested in sending commands to make queries of well-documented, non-manufacturer-specific vehicle parameters (e.g. engine coolant temperature, mass air flow, etc)? If so, then you want Mode/Service $01 and should probably start by reading SAE J1979. If you mean something else, please clarify.

OK, an update -I finally found the messages 68 49 10 10 XX CS. Thanks!

Excellent! (I had already composed the above reply before I saw this post of yours, so I went ahead and included that reply anyway.)

 

[santon]

Are you interested in sending commands to make queries of well-documented, non-manufacturer-specific vehicle parameters (e.g. engine coolant temperature, mass air flow, etc)? If so, then you want Mode/Service $01 and should probably start by reading SAE J1979. If you mean something else, please clarify.

Yes, I meant the document that I could use as a "dictionary" to interpret the commands that I get from the vehicle network and create my own commands to the car. It seems that SAE J1979 is such a document. Thanks a lot.

 

[azswiss]

Some additional reading material - J2178: Class B Data Communication Network Messages
Part 1: Detailed Header Formats and Physical Address Assignments
Part 2: Data Parameter Definitions
Part 3: Frame IDs for Single-Byte Forms of Headers
Part 4: Message Definitions for Three Byte Headers

 

[TJBaker57]

OK, an update -I finally found the messages 68 49 10 10 XX CS. Thanks!

I was getting ready to post up a reply and I see @AmpOverload and @azswiss took up the reins and jumped in and you have it already solved! I am not really surprised at that. Anyway, Here is a screenshot from that same data file I used just recently showing Engine Coolant Temperature messages...

 

[santon]

@TJBaker57 , @azswiss, and @AmpOverload - thank you guys for your help! I think this project turned out quite useful device - please see attached.

 

[TJBaker57]

Where can I find the detailed info on all of the bytes of the serial commands? I found this website but it is not so detailed (or I don't understand this info enough).

I think my journey into this arena began with that website / document many years ago.

I am building a small setup with an OLED display - a gear position indicator. Attached is the picture of the setup. Here is the video of the gear indicator in action. The final version will be smaller, and I am going to put a display in some visible place on the dash.

I for one would be very interested in details of your project. Particularly with the circuitry and Arduino code. I cobbled together both circuitry and code snippets from many sources for my J1850 project. Not having any formal training in programming or electronics resulted in me spending a lot of time getting something that works! Perhaps if you have the time you could post over in the Arduino Chat thread??

https://gmtnation.com/forums/threads/arduino-chat.22775/

 

[santon]

Perhaps if you have the time you could post over in the Arduino Chat thread??

Sure, I will post the details of this project.