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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]
Ride Sun
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  • This doesn't have anything to do with programming. Your question might be ok on https://mechanics.stackexchange.com/, they've accepted similar questions now and then in the past. Though I'm unfamiliar with their site so I'd ask on their meta if the question would be on-topic there. – Lundin Nov 13 '19 at 10:27
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    I'm voting to close this question as off-topic because it isn't about programming. – Lundin Nov 13 '19 at 10:28
  • It is about filtering CAN Bus messaged in a mobile app. How is this not about programming. I asked about a command I send over the serial bus. This is for a mobile app. – Ride Sun Nov 14 '19 at 20:43
  • Its like saying a HTTP request over the internet is not programming. – Ride Sun Nov 14 '19 at 21:19

1 Answers1

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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

MSpiller
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  • Thank u I will try that. Is there a way of sending a comand to find out what ECU addresses are on the bus before getting data? – Ride Sun Nov 14 '19 at 18:55
  • No, you need to probe by, e.g., sending TESTER PRESENT (0x3E 0x00). Note also that rather than just filtering the answers to your OBD2 (broadcast) request, you need to directly talk to the ECU by specifying the arbitration id with `ATSH`. – DrMickeyLauer Oct 27 '21 at 15:22