Dodge Diesel - Diesel Truck Resource Forums - p0122 code on 2002 Dodge cummins

i have a 2002 Dodge 5.9 cummins dead pedal i have checked everything from wires to tps to ecm individually the signal the power and the ground i tried a new tps ,took entire wire harness out of truck powered each individual wire on a head light (all good),checked power wires to ECM 2battery power 1 ignition power seemed to be good ,ground wire from ECM to the right battery, i had scan data and i could get tps angles from 0 to 100 until i started the truck, then it went to 0 percent the check engine light would come on and no throttle response (the codes were p0122 .i checked my pcm and when no throttle response pcm tps voltage from point 6 to 3.4 volts.when ecm was stuck at 0.do i need an
ECM