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Error messages "%SYS-4-NVLOG:SYNDIAGS:Module 1 detected Local Bus Stall" and "%SYS-4-NVLOG:SYNDIAGS: Local Test Mode encounters Minor hardware problem in Module" received in Catalyst 6500 Switches running CatOS software


Core issue

An improperly seated module or defective hardware may cause these messages to appear in the logs:

%SYS-4-NVLOG:SYNDIAGS:Module 1 detected Local Bus Stall

%SYS-4-NVLOG:SYNDIAGS:Local Test Mode encounters Minor hardware problem in Module #1

In addition to the SYNDIAGS:error message, you may also see this output:

Console> fn  2002 May 28 09:40:32 %SYS-4-NVLOG:SYNDIAGS:Module 2 detected Local Bus stall.

      Source: B/P. Status Register = 0xf02 enSyndiags failed on Module Number 16

    Use 'show test 16' to see results of tests.

Also, on a Supervisor Engine 2 with diagnostics set to complete, after a high availability switchover, this NVLOG is printed on the console for the new standby Supervisor Engine:

2004 Apr 30 09:19:49 %SYS-4-NVLOG:SYNDIAGS:Module 2 detected Local Bus stall. 
Source: B/P. Status Register = 0x0

This message is harmless and can be ignored.

This problem is resolved in Catalyst OS release 8.3(2) as per Cisco bug ID CSCin74096.


Verify that all modules are seated properly in the chassis. Pull out the module mentioned in the message and inspect the backplane and module for bent pins/hardware.

In order to display the errors reported from the diagnostic tests and the diagnostic level, complete these steps:

  1. Set the diagnostic level to complete using the command set test diaglevel complete.

  2. Reseat the module. With a console connection, log the boot sequence and look for any errors.

  3. Issue the show test 1 command.       

If the message persists after reseating all the modules, a hardware issue may exist.

For more information, refer to Hardware Failure Checklist for Catalyst 4000, 5000, and 6000 Series Switches Running CatOS.

If the issue is not resolved, please contact Cisco Technical Support online using the TAC Service Request Tool.

Error message