SvcWriteDataByIdentifier Timeout

A free API for the communication with control devices according to UDS (ISO 14229-1)
Rommel
Posts: 10
Joined: Sat 11. Jan 2025, 10:08

Re: SvcWriteDataByIdentifier Timeout

Post by Rommel » Tue 1. Apr 2025, 23:24

oh sorry yes I mean ReadDataByIdentifier
In this case the Tester sends a request
ECU is sending 1St Frame
Tester answers with Control frame
ECU sends 2nd Frame
after all Datas are send Tester is not anwering with a responce
And in Iso Protokoll I did not find a requriment which requires an answer after last 2nd Frame

F.Vergnaud
Software Development
Software Development
Posts: 305
Joined: Mon 9. Sep 2013, 12:21

Re: SvcWriteDataByIdentifier Timeout

Post by F.Vergnaud » Wed 2. Apr 2025, 09:43

As said before you are describing 2 different things:
- ISOTP the segmented transport protocol (ISO-15765)
- and UDS the diagnostic communication protocol (ISO-14229)
It is unclear whether the frames you are mentioning refers to a segmented UDS request or a segmented UDS response..

Here is what I understand:
1. the Tester sends a request [UDS request]
2. ECU is sending 1St Frame [UDS Response] (segmented - start of ISOTP message with ISOTP First Frame)
3. Tester answers with Control frame [UDS Response] (segmented - ISOTP Flow Control Frame)
4. ECU sends 2nd Frame [UDS Response] (segmented - ISOTP Consecutive frame)
5. after all Datas are send... [UDS Response] (segmented - ISOTP Consecutive frames)
...Tester is not anwering with a responce
Tester must not respond since it made the request and you received the response from the ECU...

Please post an extract of your CAN trace and relate it to what is going wrong with your calls to PCAN-UDS API (extracts of code alond with return status values), otherwise it is not possible to do proper support.
If you're not receiving the response in your code, then there may be something wrong with the transmitted response: the CAN trace will point it out.
Best regards,
Fabrice

Rommel
Posts: 10
Joined: Sat 11. Jan 2025, 10:08

Re: SvcWriteDataByIdentifier Timeout

Post by Rommel » Fri 11. Apr 2025, 21:31

Thanks I found the issue

Instead of 03 6E xx xx ECU answerd with 04 6E xx xx after transfering all data to ECU

Post Reply