ADCS Error -8257 occurred at ISOTP.vi

[scmm]

Hello everyone,
I have a new problem with ADCS
I'm trying to read the Ecu DTC with the "ReadDTCByStatus.vi" making the request: 18 00 FF 00 (in hex).
The Ecu has 3 errors in memory and then responds with a consecutive frame.
I've set the globals Diagnostic values: BS ​​= 255 and STmin = 0

After the request 18 00 FF 00 the ecu answers 58 03 .... , the Tester send the flow control 30 FF 00 and the ECU sends the first consecutive frames, but out of the block ReadDTCByStatus.vi I see only the first DTC.

After the Close Diagnostic.vi I've the error -8257

Can you help me?

Thank yuo very much

monica

[Ceule]

This might be a problem of an incorrect DTC format. The ReadDTCByStatus.vi has a 'DTC descriptor' input (on top) where you can configure the format of the DTCs your ECU is sending in response to this command. There are 'meaningful' defaults but those may not necessarily agree with what your ECU has. Try setting the values of that cluster to the values your ECU returns with its DTCs.

Christian

[scmm]

Hi Christian,

I tried to change the Dtcdescriptor but I think that the default settings (2-byte DTC,1 status bytes and 0 bytes AddData) are those that describe the behavior of my ECU.
To try to better explain my problem I have attached a screenshot of my project with the usual "sniffer" trace.
I hope that also this time your expert glance can help me!

thank you very much

monica

[Ceule]

Hmmmm. Very strange. The response from your ECU looks like expected, and it agrees with the DTC parameters you chose.

Also, I verified (in a port-to-port example) that the ADCS implementation of the Mixed Mode ISO TP is able to transfer messages of any byte length between 9 and 14 without error, even with the transport protocol parameters you chose (BS and STmin). I'm running out of ideas why this fails for you 🙂

Just as a try: could you run that with the default settings of BS and STmin?

BTW: What NI CAN hardware are you using and which driver version?

Christian

[scmm]

Hi Christian,

I tried the default settings of BS and STmin but the tester request changes from 18 00 FF 00 and my ecu doesn't reply because recognize an invalid format

The hardware I use is Usb 8473

Thank yuo for the help that you are giving me!

I hope this week end can "enlight" me 🐵

many thanks

monica

[Ceule]

At a careful review, I think I see now why it is failing.

ISO 15765-2 states that the FF has sequence number 0, and that the first CF after the FF should start with SN = 1. But the first CF your ECU sends has PCI byte 20, so SN = 0. This confuses ADCS, and the CF is not identified as belonging to the same message. Therefore, you only see the first DTC (from the FF) being reported, and an out-of-sequence error (-8257). This explains everything....

Christian

[scmm]

YOU are absolutely a genius!

There are no words to express my gratitude

Thanks Again

Monica