The %C6KENV-SP-2-FANUPGREQ: Module [dec] not supported without fan upgrade error message indicates that the supervisor engine and the Distributed Forwarding Card (DFC) in the specified slot require a fan tray upgrade.
A compatibility problem with the supervisor engine installed and the fan tray. The supervisor could require a high-speed fan tray.
The fan trays are mis-seated.
The fan tray is damaged.
Depending on the root cause of the problem, perform one of these steps in order to resolve the issue:
Refer to the Fan Trays section of Release Notes for Cisco IOS Release 12.2SXF on the Supervisor Engine 720, Supervisor Engine 32, and Supervisor Engine 2 for more information about supervisor engine and fan tray compatibility on Cisco Catalyst switches running Cisco IOS Software.