CPU went to STOP mode and all communication goes down

Dear Team,

I am also facing the same issue on S71500 CPU 1515-2PN (6ES7515-2AM01-0AB0) is that CPU installed in our plant around two years and working well but suddenly CPU went to STOP mode and all communication goes down and after reset the PLC POWER OFF and turns to ON it becomes normal (RUN) mode but after few days CPU again went to STOP mode and after Power reset than it moves to Connecting mode... 

And now it was not going to RUN mode even power Reset ,

Please guide us what is the root cause of CPU failure.

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Split from "User Data Failure of Hardware Component" .

I have check the Diagnostic and no previous history found in the report it only showing the current history.

And sometimes it stucks at (Connecting to...) on PLC display and we need to run the switch through manual RUN/Stop button .

When your PG/PC is connecting (using TIA Portal) to the PLC and you go online with it, does it state the PLC is in stop or run mode?

Once you are online, when you select the PLC's ONLINE & DIAGNOSTICS option in the project tree, what shows up as the first RED box entry that causes it to go into stop mode?

AutoGen_8975593

I have check the Diagnostic and no previous history found in the report it only showing the current history.

And sometimes it stucks at (Connecting to...) on PLC display and we need to run the switch through manual RUN/Stop button .

I repeat:

Once you are online, when you select the PLC's ONLINE & DIAGNOSTICS option in the project tree, what shows up as the first RED box entry that causes it to go into stop mode?

Your response indicates a lack of understanding.  Press F1-Help within TIA Portal while online with the PLC and search the help for "Online & Diagnostics" so you can find it and also how to review entries.

Once you do that, please answer the question in bold.

AutoGen_8975593

When i get online with PC/PG interface it shows stop mode