Chevrolet Suburban Computer No Communication

I Have The Suv Listed Above Bought It Had A Bad Bcm And Pcm Would Start Every Once In Awhile Got The New Bcm And Pcm, But Now Nothing No...

I Have No Spark!! Fuel Pres. Is Good. I Have Tested/replaced All Ign. Related Parts Up To The Spark Control Module In The Ecm. (i.e.- Crank...