Need some help. My '96 K2500 Suburban died on my wife while driving home. It cranks, but won't start. Checked for secondary spark - none. Checked fuses, all good. Checked coil, checked good. Replaced crankshaft position sensor on a hunch, didn't work. Borrowed a scanner & plugged in and it won't recognize that it is plugged into the truck! Checked scanner on another car, it's working fine. Re-checked fuses, all good. Ideas?