Cummins X15

Hello, I am new here. I have a 2018 peterbuilt 579 triaxle with a cummins x15. Recently I got a check engine light and put my jaltest software on it and found that it has 4 codes for injectors 3 4 5 6. So I put a set of injectors in it and a new injector wiring harness and set the new trim codes and changed fuel filters only to find that I still have the same hard codes. Code says injector mechanical system failed to respond fixed or out of adjustment. I ran a cylinder drop test and every cylinder cuts out fine. I'm at a loss at this point. Could it be a possible ecu? Please help. Need to get truck back on the road to make money.