Technical Tip: Understanding the log message 'Temperature too low'

The sample system event message will be looked like below:

level="warning" logdesc="Temperature too low" logid="0100022152" logver=604132092 msg="Fan Temperature temperature is too low: -1000.00 (-30.0 celsius degree)" status="failure

This message says the Fan's temperature is too low. Too low a temperature can cause many problems, such as problems with hard drives and the power supply.

Use the following debug command to check the actual temperature of the hardware unit:

execute sensor list
 1 PSU [1] LOST
 2 PSU [2] OK
 3 SYS Fan1 Speed 5192 RPM
 4 SYS Fan2 Speed 5192 RPM
 5 Ext Temperature 38875.00 C WARNING! <<<=====
 6 Fan Temperature 30000.00 C WARNING! <<<=====
 7 CPU_ON-DIE Temperature 41.97 C
 8 BCM_switch Temperature 49.00 C
 9 B50185 Temperature 66.50 C
10 B50210_1 Temperature 36.86 C
11 B50210_2 Temperature 39.08 C

Additional Notes:

1. Always check the FortiOS firmware version as it could be a bug issue if it is using v7.2.3. Initiate a TAC ticket to confirm whether it is a bug-related issue or upgrade to v7.2.4 and above to mitigate it.
2. Just check the temperature reading again after the upgrade.
3. Consider RMA the unit after confirming that the issue persisted.