testing CPS on a '93 4.0 HO

I know this is an XJ forum but since I'm dealing with a 4.0 HO I figure someone might know how to test a CPS.

Has anyone figured out how to test for a faulty CPS? I'm working on a '93 Grand Cherokee with a 4.0HO that won't start. I suspect that its the CPS but at $140 a pop I want to be sure. When it does this on my XJ I usually just pop a new CPS in but for my'89 XJ its only $45.

I have access to a Snap-on Scanner. Will it pick up a faulty CPS on the HO models, I know it won't on my XJ.

Also I was asked by the parts store if it had the 42RE tranny or the AW4. I thought that the 42RE were used only with the 5.2L and the AW4 wit the 4.0, is this not correct?
Thanks.

early 93's with the 4.0 had an aw4 trans, you can easily tell by looking at the trans pan, a long rectangular silver pan is aw4. a squarer black pan is the other. if you had a crank sensor problem, you would get a fault "intermittent loss on cam or crank sansor" or "no crank signal to pcm".are you having any problems?