Engine light stays on after jumping ald no flashing after jumping aldl

What is your question?

Put a new ECM in my blazer and other sensors that read bad, ran great for a week this morning I went to start my truck and it just cranks, no start. Jump a and b on aldl and engine light stays on and will not flash codes. What do I do now? It does start by jumping a and b on aldl. Pulled a and b jumper off with key off then it started right up and runs normal. Reconnected a and b and now reads a constant 12 no codes/normal. What do you think? Maybe a glitch in ECM or replace the new ECM?