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The "%C6KENV-SP-4-FANPSINCOMPAT: Fan tray and power supply 1 are incompatible error message appears in Catalyst 6500 series switches that runs the Cisco IOS system

Core issue

These messages can appear in the logs:

%C6KENV-SP-STDBY-4-FANPSINCOMPAT: Fan tray and power supply 1 are incompatible
%C6KENV-SP-STDBY-4-FANPSINCOMPAT: Fan tray and power supply 2 are incompatible
%C6KENV-SP-2-SHUTDOWN_SCHEDULED: shutdown for power-supply 1 scheduled in 300 seconds

This message indicates that an upgrade of the power supply is required in order to sufficiently operate this fan tray. Although this is a minor alarm, the overcurrent protection on the power supply can start without further warning. This additional check is introduced to avoid random shutdown of the system in the case of WS-C6K-6SLOT-FAN2 that runs at high speed, which requires more power than it can handle and causes random shut down.

In some scenarios, these messages are seen after the conversion from hybrid to native IOS, where the switch uses a High Speed fan tray (version 2) and the WS-CAC-1300W power supplies cannot handle the high speed of the Fans. This is because this type of fan tray changes the speed, which depends on the temperature.

The high-speed fan tray is used with a Supervisor Engine 720. It also works with the Supervisor Engine 2, but the switch needs to have 2500 W or a higher capacity power supply in the chassis in order to power the high-speed fan tray.

The reason why this problem did not occur on CATOS is because on the Native version fan tray type is now being detected in that version of code.

You can check type of fan tray you have on the switch with this command:

switch#show environment status

fan-tray 1:
  fan-tray 1 type: WS-C6K-9SLOT-FAN2
  fan-tray 1 version: 2
  fan-tray 1 fan-fail: OK

Note: The part number for the fan tray version 1 is the same but without the 2, like this WS-C6K-6SLOT-FAN.

The problem is that FAN2 has no IDPROM. Thus, FAN2 config is burned into the  IDPROM of the chassis. This chassis must be bought as a FAN2 config.


There are two possible resolution for such type of issues. Either downgrade to a fan tray version 1 or change the power supplies 2500W or stronger.

If you want to use FAN1, the IDPROM of chassis needs to be modified. Hence, the workaround when you use fan tray version 1 is to issue the hw-module fan-tray version 1 command in order for the fan tray version 1 to work correctly.

Error message