Facing Issues with Your ISR4331 Power Supplies – Avail This Replacement Program

Problem Description

Integrated Services Router (ISR) 4331 units shipped between October 14, 2014 and December 30, 2015 might fail to power on after an undetermined period of time.


An incorrect setting was applied to derate an internal MOSFET, which can affect the lifespan of the power supply units units sold during this time period.

Problem Symptoms

The router might fail to power on and become unusable due to a power supply unit failure in the device.


Due to the power supply unit defect, Cisco has created a proactive replacement program for these power supply units. Customers with affected units should replace their power supply unit, even if they have not experienced a failure.

Use either the power supply unit serial number or the chassis serial number for verification of the affected units. You can verify affected serial numbers with the Serial Number Lookup Tool.

Also, refer to the Hardware Installation Guide for instructions on how to replace the power supply on an ISR4331.

How To Identify Hardware Levels

View the output from the show inventory command or reference the sticker on the chassis for the serial number.

4331-BR2#show inventory 
  NAME: "Chassis", DESCR: "Cisco ISR4331 Chassis" 
  PID: ISR4331/K9 , VID: V01, SN: FJC1935D192


Also, verify a faulty unit with the power supply unit’s serial number as well. See this picture for where to find the serial number on the power supply.

Use the Serial Number Lookup Tool in order to verify the serial numbers to be sure your unit is affected.

Note: If there are any customer modules installed in a unit with this issue, remove and install them in the replacement unit. The replacement units do not come with customized modules.


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