Depends on the definition of "malfunctioning"...
As a gross general rule, common problems generally are picked up by the Drive's own internal watchdog systems. So the only thing an average person might be able to see on the output or DC bus will be the really bizzaro stuff that might even stump a seasoned drive technician. If you ARE a seasoned drives technician, you would not ask this question, so we can assume you are not.
Do you have something going on right now that you want to talk about?