In SRX platforms each Power entry module contains a fan which when experiencing a problem will generate a minor alarm on the device.

This KB explains the steps to troubleshoot and resolve this alarm seen for "PEM 0 FAN Failed".

Below chassis alarm is recorded on the device.

user@router> show chassis alarms

node0:

--------------------------------------------------------------------------

0 alarms currently active

Alarm time Class Description

node1:

--------------------------------------------------------------------------

1 alarms currently active

Alarm time Class Description

2024-01-09 11:51:32 UTC Minor PEM 0 Fan Failed <<<<<<<<<<<<<<<<<<

Here is the continuous log messages recorded for this chassis alarm.

Jan 9 11:37:20 JTAC-SRX alarmd[1746]: Alarm cleared: Pwr supply id=33554533, color=YELLOW, class=CHASSIS, reason=PEM 0 Fan Failed

Jan 9 11:37:20 JTAC-SRX craftd[8251]: Minor alarm cleared, PEM 0 Fan Failed

Jan 9 11:37:22 JTAC-SRX chassisd[1754]: CHASSISD_SNMP_TRAP6: SNMP trap generated: Power Supply OK (jnxContentsContainerIndex 2, jnxContentsL1Index 6, jnxContentsL2Index 0, jnxContentsL3Index 0, jnxContentsDescr node1 PEM 0, jnxOperatingState 2)

Jan 9 11:37:35 JTAC-SRX alarmd[1746]: Alarm set: Pwr supply id=33554533, color=YELLOW, class=CHASSIS, reason=PEM 0 Fan Failed

Jan 9 11:37:35 JTAC-SRX craftd[8251]: Minor alarm set, PEM 0 Fan Failed

Jan 9 11:37:37 JTAC-SRX chassisd[1754]: CHASSISD_SNMP_TRAP6: SNMP trap generated: Power Supply failed (jnxContentsContainerIndex 2, jnxContentsL1Index 6, jnxContentsL2Index 0, jnxContentsL3Index 0, jnxContentsDescr node1 PEM 0, jnxOperatingState 6)

Jan 9 11:37:50 JTAC-SRX alarmd[1746]: Alarm cleared: Pwr supply id=33554533, color=YELLOW, class=CHASSIS, reason=PEM 0 Fan Failed

Jan 9 11:37:50 JTAC-SRX craftd[8251]: Minor alarm cleared, PEM 0 Fan Failed

Jan 9 11:37:52 JTAC-SRX chassisd[1754]: CHASSISD_SNMP_TRAP6: SNMP trap generated: Power Supply OK (jnxContentsContainerIndex 2, jnxContentsL1Index 6, jnxContentsL2Index 0, jnxContentsL3Index 0, jnxContentsDescr node1 PEM 0, jnxOperatingState 2)

Jan 9 11:38:10 JTAC-SRX alarmd[1746]: Alarm set: Pwr supply id=33554533, color=YELLOW, class=CHASSIS, reason=PEM 0 Fan Failed

Jan 9 11:38:10 JTAC-SRX craftd[8251]: Minor alarm set, PEM 0 Fan Failed

Follow the below steps to troubleshoot "PEM 0 FAN Failed" :

Check the output of "show chassis environment" to confirm all other hardware components status on the device.

user@router> show chassis environment no-forwarding

Class Item                          Status    Measurement

Temp PEM 0                         OK        35 degrees C / 95 degrees F

     PEM 1                         OK        35 degrees C / 95 degrees F

     PEM 2                         OK        35 degrees C / 95 degrees F

     PEM 3                         OK        40 degrees C / 104 degrees F

user@router> show chassis power detail node 1

node1:

--------------------------------------------------------------------------

PEM 0:

 State:    Online

 AC input: OK (2 feed expected, 2 feed connected)

 Capacity: 4100 W (maximum 4100 W)

 DC output: 627 W (zone 0, 11 A at 57 V, 15% of capacity)

=========================

• Reseat the affected PSU on the device to rule out transient issues on the PSU. 
• For the "PEM 0 FAN Failed" alarm reseat PSU 0 on the device
• If above does not clears the alarm try power-draining the device to rule out any issue on the chassis.
• If none of the above steps helps then PSU 0 will require a RMA. Please open a JTAC case for further assistance.