Injector problem
 

Ok, I was working on a guys truck and its an 06 3500 with a 24valve cummins. And pulled codes and it shows to have injector group B circuit open. The truck runs, but only on cylinders 1,2,&3. Pulled valve cover and harness checked voltage and ohms on every injector and harness. While running it will surge on I get voltage on injectors 4,5,6. I'm thinking the ecm is fried. Any suggestions?

Anyone ideas?