What are some failure modes and causes and effects of these failures for communication of fault information on J1939 network?

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naseeam

Joined Jan 4, 2017
71
Please consider Electro Hydraulic Power Steering (EHPS) System installed in a commercial truck. It has dual motors and dual pumps and dual pump Electronic Control Units (ECUs). These pump ECUs communicate with other ECU over public J1939 network.

Embedded steering software executes in pump ECUs. One function of this software is to communicate diagnostic fault codes to service tool and Instrument cluster. And communicate power consumption to energy management system.

What are some failure modes, causes of failures, and effects of failure for this function? Are following the failure modes:

  1. Does not communicate diagnostic fault codes to service tool and instrument cluster. And does not communicate power consumption to energy management system. Is following cause of this failure?
    1. Incorrect J1939 source id or incorrect CAN identifier or other parts of message incorrect or incorrect checksum? What are some effects of this failure?
  2. Erratically communicates diagnostic fault codes to service tool and instrument cluster. And erratically communicates power consumption to energy management system. What are some causes and effects of this failure?
  3. What are some other failure modes for this function. And what are some causes and effects of those failures?
 

Irving

Joined Jan 30, 2016
2,669
No, it's not homework. I'm not in school.
OK, forgive me, but it just sounds a bit like "I've been asked this question but I can't be bothered to do any reading/research myself, so I'll repeat it here and see what answers I get".

I could answer it, but I don't have the time to write a treatise on J1939 error handling, or the underlying CAN media/signalling error handling/recovery. Its all covered in depth in the SAE documentation. You might also find something useful in the following:

https://embeddedflakes.com/j1939-diagnostics-part-1/
https://embeddedflakes.com/j1939-diagnostics-part-2/
https://embeddedflakes.com/network-management-in-sae-j1939/
https://lnx.numeralkod.com/wordpres...mode-identifier-fmi-codes-on-j1939-data-link/
https://piembsystech.com/can-bus-error-handling-in-can-protocol/
 
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