Mac Pro (2019) has a status indicator light on top of the computer, next to the power button. There is also a second status indicator light on the back of Mac Pro near the power port.
When Mac Pro is turned off, the status indicator light does not illuminate.
Turned on or in sleep mode
After Mac Pro turns on or goes to sleep, the status indicator light is solid white and remains on until the computer turns off.
If there is a memory detection or data error, the status indicator light is solid amber for 0.2 seconds and repeats every second. Verify your memory and install or replace memory if necessary.
Housing unlocked while computer is on
If the housing is unlocked while the computer is on, the status indicator light is solid amber for 0.3 seconds and repeats until the housing is locked. Make sure the top latch is completely locked:
Top: Locked position (dots match)
Bottom: Unlocked position (dots do not match)
PCIe card error
If Mac Pro encounters an error with a PCIe card, the status indicator light flashes amber twice and repeats until the computer is powered off. If you recently installed a PCIe card, learn how to resolve PCIe card errors on your Mac Pro.
Power button pressed while housing is removed
If the housing is unlocked and the power button is pressed, the status indicator light is solid amber for half a second. Make sure the housing is fully seated and locked, then try starting up your Mac Pro again.
Firmware recovery mode
If Mac Pro is in Firmware recovery mode, the status indicator light rapidly flashes amber three times, briefly flashes amber three times, then rapidly flashes amber three times. This repeats until the computer is powered off. You might need to restore the T2 Security Chip on your Mac Pro. If you still need help, contact an Apple Authorized Service Provider.