What this article covers
Details diagnostic CLI commands and physical checks to troubleshoot redundant Power Supply Unit (PSU) loss, power redundancy degradation and false failure alarms on FortiGate firewalls.
ScopeFortiGate enterprise models equipped with dual or hot-swappable AC/DC power supplies (FG-1000F, FG-1800F, FG-2600F, FG-3000D, FG-4000F series).
Before using the CLI
PSU seatingConfirm that each hot-swappable supply is fully seated and latched.
Power feedCheck power cables, outlets or PDUs and redundant feed availability.
Rear LEDsCompare PSU status LEDs with the chassis or hardware guide.
On-site workflow
Inspect the physical power path
Verify PSU seating, power-cable connections and rear-panel status LEDs. Record which supply or feed is reporting the fault.
Query PSU hardware status
Capture the PSU state reported by FortiOS.
diagnose hardware deviceinfo psuReview hardware sensor output
Look for PSU1 Status, PSU2 Status, voltage and related sensor entries.
execute sensor listCheck system event logs
Filter and review system events for power-supply alarms and transitions.
execute log filter category 1
execute log displayDecide whether TAC or RMA is required
When an alarm begins after a firmware upgrade, verify PSU-controller firmware compatibility. Open a TAC case or RMA request when the PSU remains unpowered.
Operational caution
Review before applying: Do not remove the only active power supply from a production appliance. Confirm that redundant power is genuinely available before reseating or swapping hardware.