Field Notice: FN74386 - Cisco IOS XR Software May Display False Fan Alarms and/or Outputs for PSU2KW Power Supplies - Software Upgrade Recommended

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Updated:April 1, 2026
Document ID:FN74386

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Low
Impact Rating:
Low
First Published:
2026-Apr-01
Last Published:
2026-Apr-01
Revision:
1.0
Cisco Bug IDs:

Notice

THIS FIELD NOTICE IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTY OF MERCHANTABILITY. YOUR USE OF THE INFORMATION ON THE FIELD NOTICE OR MATERIALS LINKED FROM THE FIELD NOTICE IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS FIELD NOTICE AT ANY TIME.

Products Affected


Affected Product Name Description Comments
8101-32FH Cisco 8100 32x400G QSFPDD 1RU Fixed System w/o HBM  
8201-24H8FH Cisco 8201 1RU System w/ 8x400GE QSFP56-DD&24x100GE QSFP28  
8201-32FH Cisco 8200 32x400G QSFPDD 1RU Fixed System w/HBM  
8201-SYS Cisco 8201 Chassis w/ 24x400GE QSFP56-DD&12x100GE QSFP28  
8202-32FH-M Cisco 8200 2RU Chassis w/32x400G, XR SW, HBM & MACsec  
8202-SYS Cisco 8202 Chassis w/ 12x400GE QSFP56-DD&60x100GE QSFP28  
8212-48FH-M Cisco 8212 2RU System w/ 48x400GE QSFP56-DD with MACsec  
PSU2KW-ACPI 2000W AC Power Module with Port-side Air Intake  




Defect Information


Defect IDHeadline
CSCwk03525New firmware binary for new PSU design
CSCwf08657Feature - New 2KW AC PSU support for 8000 fixed

Problem Description


Cisco has added a new design for the listed product IDs (PIDs). There is a difference between power supply unit (PSU) designs. PSUs from with the new design use a single fan, whereas PSUs from the original design feature two fans.

Cisco IOS XR Software images from releases earlier than Release 24.4.1 do not differentiate between these hardware versions and expect two fans for all units, resulting in a field-programmable device (FPD) alarm for the fan and firmware upgrade limitations on new PSUs.

Note: Users can ignore the false alarms, output, or both caused by this issue, as there is no functional problem with the PSUs. The Workaround section of this Field Notice provides SMUs to correct the issue if users prefer not to see the false alarms, output, or both. Requesting an RMA for the PSU will not resolve either the false alarm or the false output issue.


Background


Cisco utilizes multiple designs for Cisco PSU2KW-ACPI Power Supplies. While they share the same PID, the internal fan configuration differs between the single and double fan designs.

In legacy software releases, the system attempts to poll a second fan that does not physically exist on the some of the PSUs.


Problem Symptom


Users will see either the following output or an alarm, depending on which Cisco IOS XR Software release is running on the device.

  • For users who are running Cisco IOS XR Software Release 7.11.2, 7.10.2, or 7.9.2, there will be no alarm, but the system output will show NOT READY under ATR Status, as shown in the following example:

 

  • For users who are running Cisco IOS XR Software Release 24.1.2 or 24.3.2, the system output will show the alarm, as shown in the following example:

Workaround/Solution


There are two options to fix this issue:

  • Cisco IOS XR Software can be upgraded to Release 24.4.1 or later.
  • The user may load the SMU for the individual release they are using, as shown in the following table.

Cisco IOS XR Software Release

Platforms

SMU Image Name and Link

Reload or Hitless SMU
7.9.2
8101-32FH, 8201-SYS, 8201-24H8FH, 8201-32FH, 8202-SYS, 8202-32FH-M, 8212-48FH-M
 8000-7.9.2.CSCwf08657.tar Reload
7.10.2 8101-32FH, 8201-SYS, 8201-24H8FH, 8201-32FH, 8202-SYS, 8202-32FH-M, 8212-48FH-M 8000-7.10.2.CSCwf08657.tar Reload
7.11.2 8101-32FH, 8201-SYS, 8201-24H8FH, 8201-32FH, 8202-SYS, 8202-32FH-M, 8212-48FH-M 8000-7.11.2.CSCwk03525.tar Hitless
24.1.2 8101-32FH, 8201-SYS, 8201-24H8FH, 8201-32FH, 8202-SYS, 8202-32FH-M, 8212-48FH-M 8000-24.1.2.CSCwk03525.tar Hitless
24.3.2 8101-32FH, 8201-SYS, 8201-24H8FH, 8201-32FH, 8202-SYS, 8202-32FH-M, 8212-48FH-M 8000-24.3.2.CSCwk03525.tar Hitless

How to Identify Affected Products


Use show env fan and show hw fpd to verify the issue. The following output examples are for Cisco IOS XR Software releases earlier than 24.4.1.

Sample output for the show env fan command

Run show env fan. The output for a PSU with a single-fan design will show FAN_1 with a speed of 0 rpm, triggering a system alarm or false output.

Sample output for the show hw fpd command

Run show hw fpd. The status for a single-fan PSU (typically PM0 or PM1) will display NOT READY, as shown in the following example:

image.png

Note: When the system is running Cisco IOS XR Software Release 24.4.1 or later or recommended SMUs are loaded, the FAN_1 entry is correctly omitted, and no alarm or false output is generated, as shown in the following example:

 


Revision History


VersionDescriptionSectionDate
1.0Initial Release—2026-APR-01

For More Information

For further assistance or for more information about this field notice, contact the Cisco Technical Assistance Center (TAC) using one of the following methods:

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