When an old PEM is replaced with a new one, the serial number of the new PEM should appear in the output of 'show chassis hardware'. This article describes a situation where the old (stale) serial number does not get updated and explains how to clear it.

An old PEM was replaced with a new one, but the output of 'show chassis hardware' still displays the serial number of the already removed PEM instead of the serial number of the currently running newly installed PEM.

During a scheduled maintenance window, Perform below actions to clear the stale serial number. 

Note: The following commands will cause ALL FPCs to reconnect with chassisd and will impact traffic passing through this device. 

1. Non GRES Mastership Switchover 

Check the output of 'show chassis hardware | match PEM' to verify if the stale SN is cleared. If not, then go to step 2.

2. Restart Chassisd Process