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can-busobd-iielm327

How can I talk only to one ECU in a two ECU Car with ELM237 and OBDII

I am sending following ELM237 commands to a Porsche Cayenne. There are two ECU on the Bus 7E9 and 7E8. I would like to address only one at a time. I thought I can do that by using atsh7E8 to talk only to one but then the answers contain only the string 'NODATA'. I guess I miss something here to filter one ECU at a time. Does somebody have an idea?

Request/Response
[atd, OK],
[atl0, atl0OK],
[ate0, ate0OK], 
[ath1, OK], 
[atsp0, OK],
[ats0, OK],
[atat1, OK],
[ate0, OK],
[0100, 7E9064100981880017E8064100BFBEA893],
[0120, 7E8064120A007B1197E906412000000001], 
[0140, 7E8064140FED085007E9064140E0800000],
[atdp, AUTO,ISO15765-4(CAN11/500)],
[0900, 7E9064900144000007E806490055400000],
[0902, 7E810144902015750317E821414332413231477E8224C413839303838], 
[010C, 7E904410C09607E804410C095C],
[010D, 7E903410D007E803410D00]
Solution

  • I suppose by addressing you mean, you want to see the messages of only one ECU at a time. In your example above you are not sending any messages to the car.

    Filtering the received messages be done by using the Receive Filtering command of the ELM237

    AT CRA 7E8

    After that you will see only the messages sent with ID 7E8