Description

This article explains the major/minor alarms "FPC X Hard errors", "FPC X Temp Sensor Fail", and "FPC X Volt Sensor Fail" observed, their causes, and steps to mitigate the issues.

Symptoms

We would be seeing logs similar to the ones shown in below example: 
Juniper@Router> show chassis alarms
--------------------------------------------------------------------------
3 alarms currently active

Alarm time Class Description
XXXX-XX-XX XX:XX:XX +03 Minor FPC XX Temp Sensor Fail
XXXX-XX-XX XX:XX:XX +03 Major FPC XX Hard errors
XXXX-XX-XX XX:XX:XX +03 Minor FPC XX Volt Sensor Fail

The below Logs are seen on the messages file:

Apr X XX:XX:XX.XXX XXXX SRX alarmd[24146]: %DAEMON-4: Alarm set: FPC id=83887976, color=YELLOW, class=CHASSIS, reason=FPC 7 Temp Sensor Fail

Apr X XX:XX:XX.XXX XXXX SRX craftd[23319]: %DAEMON-4: Minor alarm set, FPC XX Temp Sensor Fail

Apr X XX:XX:XX.XXX XXXX SRX alarmd[8425]: %DAEMON-4: Alarm set: FPC id=16778088, color=RED, class=CHASSIS, reason=FPC 7 Hard errors
Apr 9 00:30:00.251 2024 SRX craftd[8321]: %DAEMON-4: Major alarm set, FPC XX Hard errors

Apr X XX:XX:XX.XXX XXXX  SRX alarmd[24146]: %DAEMON-4: Alarm set: FPC id=83887976, color=YELLOW, class=CHASSIS, reason=FPC 7 Volt Sensor Fail
Apr 9 00:30:00.251 2024 SRX craftd[23319]: %DAEMON-4: Minor alarm set, FPC XX Volt Sensor Fail

Solution

The "FPC XX Temp Sensor Fail" alarm indicates that there is a failure in the temperature sensor of FPC XX. This means that the device is unable to accurately measure the temperature of the FPC XX, which is critical for ensuring proper functioning and preventing overheating issues.


The "FPC XX Hard errors" alarm indicates significant errors detected on FPC XX, which could be related to hardware malfunctions or failures in processing data, this proves to be a hardware issue with FPC


On the other hand, the "FPC XX Volt Sensor Fail" alarm indicates a failure in the voltage sensor of FPC XX. This means that the device is unable to accurately measure the voltage levels on FPC XX, which are essential for ensuring stable and reliable power supply to the components on the FPC.

Before proceeding with RMA for the FPC (linecard), please follow the procedures below:

  1. Check Related EventsReview any related events that occurred at or just before the log message to gather hints on the possible cause of the problem. Also collect the show chassis related commands at the time of the issue.

  2. Reboot / Reseat the FPC (Linecard) and CB

    • Soft Restart: Use the following command to perform a soft restart:
      request chassis fpc slot <slot-number> (offline | online | restart)
    • Soft Restart CB: To restart the CB you could try these commands - request chassis cb slot # offline / online.

  3. Stabilization
    Wait for the FPC and CB to stabilize before concluding it to be a hardware issue, especially if the FPC/CB or router was recently rebooted.

     

Helpful Commands for Troubleshooting:

  • show chassis environment cb
  • show log messages
  • show chassis fpc
  • show system alarms

Modification History

2024-09-16: New KB Written.

2025-02-27 : dconejomora
Removing the following step from the KB 

  • "Hard Reseat: Physically remove and reinsert the FPC during a maintenance window. Ensure the FPC module is clean when reinserted"

We should not ask the customer to complete any physical re-seat