P CODES (POWERTRAIN) P1400 - P1499 P1418 Questions

I Retrieved A P1418 Obd2 Trouble Code On My 325i. What Is The Definition For This Code And How Do I Address It?

I Have A Trouble Code Of P1418 - Split Air 1 Circuit Malfunction. What Does This Mean And Where Is It Located On My Car? Is It A Major...