yes the pcm receives signal from crank and cam sensors then pcm grounds auto shut down relay witch sends 12v to coil then pcm also dwells coil on the ground side so make sure you have 12v at pin 30 and 86 of auto shut down relay and check for codes in pcm if no codes check to see if there is an rpm signal when cranking this is read from the crank sensor and check if pcm is actually grounding relay if not it isnt getting crank or cam signal or pcm is possibly down due to no 12v or ground to pcm or faulty pcm oh yeh also if a 3 wire sensor shorts like in the trans or under hood sensors could shut pcm down but it is still good though just have to unplug one sensor at the time to see if it comes back to life i have run accross this a few times also
and make sure it's not something simple like the coil itself witch is common faillure on these trucks i'm just assuming you checked 12v at coil when engine is cranking over that is the only time 12v will be there you can check all day with key on not cranking you will get 0v this the easiest way and most efective way i know to check for no spark oh the relay pin numbers are printed under relay