Tester Present Problem in PCAN UDS

A free API for the communication with control devices according to UDS (ISO 14229-1)
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Shail
Posts: 25
Joined: Tue 28. Apr 2020, 10:09

Tester Present Problem in PCAN UDS

Post by Shail » Thu 20. Aug 2020, 12:05

Hello,

I am using the PCAN UDS API testDiagnosticSessionControl to send ECU to boot mode.

1) In the sample code of C++ PCAN UDS API where the tester present request send since we are not able to find any specific function which sending tester present?
printf(" Assert that Auto TesterPresent Frame is sent...\n");
Sleep(2000);
printf(" Should transmit an Auto TesterPresent Frame\n");

We do not want to use programming request to send ECU in boot mode but the problem is in programming request only tester present request is send.
2) If we do not want to use diagnostic request how we can send tester present service cyclically to make session alive? Should we can send dummy positive response of tester present from ECU to work?

3) Due to absent of tester present security service is not working. How to handle this to scenario?

Thanks in advance.
Attachments
Please check log file and see that due to absent of tester present security service is not working.
Please check log file and see that due to absent of tester present security service is not working.
Issue_tester_present.png (12.12 KiB) Viewed 589 times

K.Wagner
Software Development
Software Development
Posts: 767
Joined: Wed 22. Sep 2010, 13:36

Re: Tester Present Problem in PCAN UDS

Post by K.Wagner » Thu 20. Aug 2020, 15:06

Hello,
Shail wrote:
Thu 20. Aug 2020, 12:05
1) In the sample code of C++ PCAN UDS API where the tester present request send since we are not able to find any specific function which sending tester present?
Note that entering a session other than the default (DSC_DS) activates an automatic mechanism designed to keep alive non-default diagnostic sessions without interaction of the user. This is part of the specifications and It is not possible to change this behavior.
Shail wrote:
Thu 20. Aug 2020, 12:05
2) If we do not want to use diagnostic request how we can send tester present service cyclically to make session alive? Should we can send dummy positive response of tester present from ECU to work?
you can use the function SvcTesterPresent within a default session, using a thread or a timer to do this periodically. Check the UDS documentation on page 153 for more information on SvcTesterPresent.
Shail wrote:
Thu 20. Aug 2020, 12:05
3) Due to absent of tester present security service is not working. How to handle this to scenario?
Send the TesterPresent for your own as described in point 2.
Best regards,
Keneth

K.Wagner
Software Development
Software Development
Posts: 767
Joined: Wed 22. Sep 2010, 13:36

Re: Tester Present Problem in PCAN UDS

Post by K.Wagner » Thu 20. Aug 2020, 15:55

Hello,

regarding my answer on TesterPresent:
K.Wagner wrote:
Thu 20. Aug 2020, 15:06
Note that entering a session other than the default (DSC_DS) activates an automatic mechanism designed to keep alive non-default diagnostic sessions without interaction of the user. This is part of the specifications and It is not possible to change this behavior.
It is indeed possible to suppress the TesterPresent automatic sending on non-default sessions. You need to change the UDS session information using the function SetValue to be of type DSC_DS. This change affects only the API client, not the ECU. You will find an example on page 93 of the UDS documentation.

Thanks to F.Vergnaud for bringing this to my attention.
Best regards,
Keneth

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