1996 Chevy S-10

Your saying it cranks good but won't start? Battery has a full charge and all battery conections, on both ends are clean and tight?

At the data link connector, pin 16 has voltage and pins 4 and 5 have ground. When you turn the turn the key on, no crank, does the mil come on?

Check for reference voltage at a sensor that uses ref voltage, like the TPS, should be around 5 volts with the key on, you don't have to crank it. If no ref voltage, I'd check voltage feed and ground at the pcm. Check ecm fuses, not only check the fuses, use a voltage tester and test fuse circuit for voltage. If it says ecm ignition fuse, the circuit goes hot when you turn on the key. If it says ecm battery fuse, the circuit is hot all the time.

Yes, it is ses not mil, key on, no crank, that lite never comes on? My guess is, the computer isn't grounding the ses circuit. Check the fuse circuits I mentioned.