P0410 GMC -

Question

My emissions test failed. Put in a mass air flow sensor from a 2001 GM aurora, part was clean, not any signs of damage. Mehicic forgotten to put connector little plug back in, I drove, check light went off for a while than retured. Went back to mechic he discovered that the plug wasn't attached to the sensor and reattached. What is happing, engine light is still on!. Also have a reading for a Crankshaft position sensor, could these be related?