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Problem with DTC reading
Posted: Fri 19. Apr 2019, 10:58
by KateS
Hello,
I'm currently developing a program on C# using your APIs and I need read DTC from ECU.I use SvcReadDTCInformation(), but have problem with response.
Code: Select all
result = UDSApi.SvcReadDTCInformation(Channel, ref request, service, mask);
if (result == TPUDSStatus.PUDS_ERROR_OK)
{
result = UDSApi.WaitForService(Channel, out response, ref request, out requestConfirmation);
}
It workes fine, but when ECU answer with only one error, response.DATA shows only zeroes. Example: I want to read DTC, use this code, in PCAN-View I see (0xCF -mask, 0x07111E - one error number)
- DTC.PNG (2.22 KiB) Viewed 5743 times
But in the same time after WaitForService response.DATA is empty. In other cases it worked good(more than 1 error, anorher services). Maybe You know what is the reason?
Re: Problem with DTC reading
Posted: Tue 23. Apr 2019, 11:11
by K.Wagner
Hello,
We cannot reproduce this problem. We just used the sample code (PCUServer.exe/PCUClient.exe) for asking/simulating DTC reading, and we do receive the correct data.
- SvcReadDTCInformation_Test
- UDS_Test.PNG (57.43 KiB) Viewed 5734 times
Could you please show the whole output of the transmission with PCAN-View? we only see the first frame of a total of 19 bytes to be transmitted. It would also be helpful to know which servic3e you are passing as parameter by the function SvcReadDTCInformation.
Re: Problem with DTC reading
Posted: Mon 29. Apr 2019, 14:19
by KateS
Okey. I use 0x19 services with different subfunctions (0x02 and 0x03). In my case they shall show one and the same error (for example 0x07111E) , but they don't.
In PCAN View I see
- DTC in PCAN View.PNG (29.34 KiB) Viewed 5715 times
But I don't see the same in my code. Response for 0x19 service and 0x02 subfunction is empty for some reason, in the same time 0x19 0x03 work fine
- 0x19 in C#.png (149.84 KiB) Viewed 5715 times
When I add one more error in ECU, all work normal
- 0x19 in C# 2 errors.png (153.98 KiB) Viewed 5715 times
- DTC in PCAN View normal.PNG (28.95 KiB) Viewed 5715 times
Re: Problem with DTC reading
Posted: Mon 29. Apr 2019, 17:24
by K.Wagner
Hello,
well, for me, it seems as the ECU has a bug, i.e. it is not sending the whole data. As far as I can understand, the ECU is saying, that 7 bytes will be sent using multi-frame: first frame, length of 7 bytes, i.e. 6 data bytes as "
59 02CF 07 11 1E". The 7th bytes is never received (no consecutive frame).
- One Byte is Missing
- OneByteMissing.PNG (18.81 KiB) Viewed 5714 times
Though, the whole 7 bytes should actually be sent in a single frame, as stated in the ISO 15765-2 specifications. Only longer messages should use multi-frame for sending. The data being sent from your ECU should be "
07 59 02 CF 07 11 1E
XX", where
7 is the data length, and
XX is the failing byte.
You also are looking at the data before checking if the result of calling WaitForService is OK.
- CHecking data before checking result
- CheckResult.PNG (12.68 KiB) Viewed 5714 times
Note that the function is possibly returning
PUDS_ERROR_NO_MESSAGE, since the message was never received completely.
Re: Problem with DTC reading
Posted: Tue 30. Apr 2019, 07:32
by KateS
Looks like you are right, thank you