Cisco GSR12/60 - 12012 Router -AnyLAN, SONET/SDH Installation And Configuration Manual page 218

Troubleshooting Overview
For example, if there is a problem with the –48 VDC line that supplies the blower
module, the system will start up, but will also recognize that the blower is not operating.
The system will initiate a blower failure shutdown sequence, display the appropriate
warning messages, then shut down after two minutes. If there is a problem with any of
the other DC lines, the RP will not be able to initialize the system software, so the
system might attempt to start up and fail during the boot sequence.
Depending on when the red output OK LED goes off, proceed as follows:
— If the input OK LED (or AC OK LED on an AC-input power supply) stays off (if it
— If the input OK LED (or AC OK LED on an AC-input power supply) goes on
— If the input OK LED (AC OK LED on an AC-input power supply) goes on, and the
— If the red output fail LED (common to both AC-input and DC-input power supplies)
5-6 Cisco 12012 Gigabit Switch Router Installation and Configuration Guide
never goes on) when you turn on the power switch, there is a problem with either
the DC (or AC) source power or the DC power that is distributed to the internal
components. Proceed to the section "Troubleshooting the Power Subsystem."
temporarily, then goes off within 30 seconds, the system is most likely shutting
itself down because it detected an out-of-tolerance power or temperature condition
within the power supplies. Proceed to the section "Troubleshooting the Power
Subsystem."
system starts up as expected but then displays the following message and shuts
down after two minutes, there is a problem with one of the blower modules. Proceed
to the section "Troubleshooting the Cooling Subsystem."
%ENVM-2-FAN: Fan has failed, shutdown in 2 minutes
stays off, yet the system starts up correctly, displays the preceding message, and
then shuts down after about two minutes, there is a problem with the –48 VDC line
to the blower module. Proceed to the section "Troubleshooting the Power
Subsystem."