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I have a VW Golf 4, which is quite old and talks KWP 2000 (ISO 9141) on its CAN bus. I use a dongle powered by ELM 327, connected to the OBD-2 port of the car.

I am trying to send messages individually to each ECU. I tried to change the header of the messages: AT SH 48 XX F1 (I hoped XX would be the ECU ID; 48 is the flag for "use physical addressing"). Any command I issue (e.g. tried 3E for "tester present") returns NO DATA (I disabled automatic timeouts and set the timeout to maximum value).

Is there a way to send messages directly to the ECU? I am not interested in the set of data provided via OBD-2, neither do I want to re-flash the ECUs. At the moment I just try to find out which ECUs are available on the bus.

Thanks!

csima
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1 Answers1

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VW works on Transport Protocol TP 2.0, hence you need to initialize with 0x200 header.

https://jazdw.net/tp20

See above link for more info.

Soumya Sen
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