Rather generic question and I'm trying not to give a general answer. It can do all of the above. Generally, there are IDM code thrown when the pcm detects there is a possible signal issue. Run the codes with AE, NGS, or MT2500. A generic "autozone" or whatever scanner won't tell you crap.
Depending on the codes, I can help you narrow down the problem.
Most of the time, it's a UVCH issue or a engine harness issue. But to be fair, I've seen my share of dead IDM's. A buddy's truck died.. when they pulled the IDM.. it was full of water.