How to display status for On, Off, Faulty

I have a table which shows whether devices are ON or OFF.
Currently, it looks like this

Status Name Some other columns
? DeviceA
? DeviceB
? DeviceC

There is a new requirement, which is to show devices which are FAULTY.
A faulty device can be ON or OFF.

The most straightforward solution would be to put the FAULTY label next to the ON/OFF icon, like so

Status Name Some other columns
? DeviceA
? FAULTY DeviceB
? FAULTY DeviceC

However, I'm concerned about users confusing the ? for FAULTY

Some possible alternatives I've considered:

  • Spell out ON OFF instead of using ??
  • Make FAULTY its own column, instead of sharing a column with ON``OFF
  • Find an appropriate icon for FAULTY & possibly HEALTHY

What would be the best solution?

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