no start-no run problem

brain hurts now. been working on this problem for a week. 2008 solstice convertible 2.4 auto. it started out as a no start-no run problem. scan all control modules. codes were u2105, u2129, u2107, u0140, u0155,
and u0100. all were about lost communication to bcm-ecm-tcm modules. check all wire harnesses, did the ohms and voltages check out. found the ecm not working with others. replaced new ecm. clear codes and
start-run engine. scan running engine for codes. p0315 ckp system variation not learning and p0602 ecm not programmed came up. went to stream data to check crank-cam counts. crank count was showing working. the intake cam count was working. the exhaust cam count not working.swap out both cam sensors and the same result. exhaust not working. check volts 5v to the correct pins. now here is where im stuck. if i clear codes in ecm i can start-run engine. turn off and start-run engine. did it for 5 cycles. if i start-run engine then turn off engine and count to 30secs. no start-run engine. but clear codes in ecm then start-run engine. ok now what am i missing here. i have a genesys 5 scanner so i can get into the computers good. please anyone can help me. thanks and sorry for the long post.

Was the PCM programmed or flashed to the Vin number?

Also, when a PCM is changed, you have to perform the crank variation relearn procedure......need a GM scan tool to do that...