OBD Connect via CAN

[falkpl]

I am attempting to connect to a OBD ECU using a usb8473 and CAN.  I think I have the physical connection correct but I get the a timeout error when calling the ADCS toolkit OBD Open.  What I dont know is how to determine the baud rate and Tx/Rx IDs.  Where is this information.  How can I determine the cause of the problem.

[Mr.F]

Hi Pual,

That information will be contained in the A2L file that corresponds to your ECU. Do you have this file?

[falkpl]

I dont have this file, where can I get?  I am newer to ODB.

[Mr.F]

Hi Paul,

Sorry I was mistaken with your setup you won’t have an A2L file. One thing you can do I open up Bus Monitor and see what baud rate allows you to receive transmissions.  Do you have any more information regarding the ECU to obtain these parameters?

[falkpl]

The only information I have is that it is a ford f250 diesel truck (2009?). I Have acess to a can line that is validaetd to work (another companies tools work on it) I am trying to find out about the reciever and transmitter id and Baud rate but have not had luck yet.
Is my best bet to try a bunch of baud rates and see if any bus traffic is noted. The can module passes the self test but this is as far as I have gotten.
I am just trying to get the PID supported querry to work, is this I should at least get a response, all else seems trivial, I have to get a few engine parameters at ~ 1Hz.

[Mr.F]

Hi Paul,

If you can read from the CAN network using Bus monitor you will be able to see any messages being transmitted and received. Unfortunately, I don’t have any more information regarding your particular ECU’s baud rate or arbitration IDs. That information is specific to your vehicles CAN system.

[_Bryan]

Hey Paul,

Did you ever get any more info about connecting with the F250?

I am trying to find a way to get engine oil temps (EOT) off my truck, but it is not a standard can message and was thinking about messing around with LabVIEW.

I tried looking for an option to PM you, but it is not possible on this forum.

[Raj_V]

Hey Bryan,

If the EOT is not a standard CAN message, how exactly do you plan on getting this data using LabVIEW? If the message is passed through the CAN bus, you would need to find the arbitration ID of the specific message, so that you can get that data off the bus. 

[_Bryan]

That is correct.  If I can find the right person they will have that information and it will all be possible.

[Raj_V]

Bryan,

one other thing to consider is using the Automotive Diagnostic Command Set. The product page can be found at the link below.

https://www.ni.com/en-us/shop/product/automotive-diagnostic-command-set-toolkit.html

If your F250 is newer than 2006, it most likely has an ODB2 interface for you to be able to use the command set. This might be easier to use as it abstracts the arb id's and might help you get what you are looking for. I would also look into getting in touch with the manufacturer to find out exactly what you need to communicate to get the specific data you are looking for.