I have an old scanner hand held I had a body shop that I deliver paint to they ordered me a BMW MASS AIRFLOW SENSOR I replaced it on Saturday morning I did not disconnect the battery the car idled good so on Sunday morning I went for Gas and the car started to idle erratic and the service light came on so I put the old Sensor back and cleared the codes 1415 the car runs fine just erratic idle when stopped at a light Any Ideas thank you very much for getting back to me I appreciate it anything you can think of that I did wrong 😑