Welcome to J2534-Sharp Discussions!

[BrianHumlicek]

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[jglim]

Hi Brian,

Just wanted to thank you for a great library! It is in use in a small open-source diagnostics tool, and it's a good feeling to be able to focus on the reverse-engineering aspect of my project instead of the J2534 plumbing :)

[BrianHumlicek]

Thanks for letting me know. I built this exactly for this reason; so you can get right to the meat of your J2534 project without having to learn all the intricacies of the unmanaged API.

You're welcome, and best of luck with your project!

Brian

[waynemodz]

Hey Brian,
Interesting project you got going on, this is related to my space and unfortunately c# is my only language.
I see the package is no longer under the the nuget repo,

tried to run a test here ,
`
byte Msg = 0x0C;
byte Cks = Checksums.CalculateISO9141(new byte[] { 68, Msg });

            Channel.SendMessage(new byte[] { 0x33, Msg, Cks });
            GetMessageResults Response = Channel.GetMessage();
            foreach (var M in Response.Messages)
            {
                PrintF("RESP: "+M.Data.Message);
            }

`

` public static byte CalculateISO9141(byte[] data)
{
byte checksum = 0;

        foreach (byte b in data)
        {
            checksum ^= b; // XOR operation
        }

        return checksum;
    }`

i get an INDEX ARRAY error,
and then the device wont connect until i restart the program.
Is there any further documentation or examples?

[BrianHumlicek]

What line is the exception happening on and what exactly is the exception? Are you sure this is a problem with J2534Sharp?

Brian

[waynemodz]

thank you for your reply, so this car i'm testing on uses KWP2000 which should be ISO9141, i'm getting a BUFFER_EMPTY response. 0x0C should be engine speed rpm, so was just doing a test too get that. Only data i managed to get was battery voltage.

[czechu82]

Hi Brian,

I'm trying to build simple diagnostic app .
How do i set up can ID and filters correctly ?
Example :
Tool Id -> 1F 40 10 F2
ECU id -> 1F 40 F2 10
ISO15765 , Baud 500 , channel 1

your code :
MessageFilter FlowControlFilter = new MessageFilter()
{
FilterType = Filter.FLOW_CONTROL_FILTER,
Mask = new byte[] { 0xFF, 0xFF, 0xFF, 0xFF },
Pattern = new byte[] { 0x00, 0x00, 0x07, 0xE8 },
FlowControl = new byte[] { 0x00, 0x00, 0x07, 0xE0 }
};

My main goal is to read Raw data coming from the server.
How can this be done using your code ?
GetMessageResults Response = Channel.GetMessage(); ?

Also can you explain bytes in this command:
Channel.SendMessage(new byte[] { 0x00, 0x00, 0x07, 0xE0, 0x01, 0x00 });
looks like first 4 bytes are ID and last 2 (0x01,0x00) are raw data ?

Regards

[czechu82]

Thanks Brian !

It works but I had to set it on the channel.

I'm still having small issues filtering messages.
For some reason empty massages are added to queue.

Based on this article only pattern ID should be added to queue.
https://www.opusivs.com/support/j2534-support/passthru-sae-j2534-dll/passthrustartmsgfilter

    Pattern = new byte[] { 0x1F, 0x40, 0xF2, 0x10 },

I'm trying to read raw data and my current output looks like this :

1F 40 10 F2 10 03
1F 40 10 F2 <- this goes to queue after 10 03 request and when i try to read UDS response it shows empty message.
1F 40 F2 10 50 03 00 19 01 F4 <- 2nd try shows correct response

Is it wrong filter set-up or something else?

Regards

[BrianHumlicek]

Try adding this before you send the message.
Channel.SetConfig(Parameter.LOOP_BACK, 0);
Additionally, you may need to discard received messages with RX flags set. These are sometimes used as tx receipts by the device. They aren't physical messages that are received over the bus.

[czechu82]

Setting LOOP_BACK, 0 didn't work. I believe its set to 0 by default.
When set to 1 it adds 00 00 00 00 to queue.

Want to set RX flags but cant find any info how its done.

[czechu82]

For now i fixed it in the app by setting condition if message length <= 4 then read response again , but still I'd like to fix it the proper way by setting RX flags if possible .

[BrianHumlicek]

You don’t set RXflags, you read them. Instead of checking if the length is greater than 3, check if the flags are clear (equal to zero).