The light will come on when you typically have a chip or tuner and you get the boost levels above stock boost levels. You are not hurting anything; it is just going to de-fuel to keep you (in Fords terms) in the safe zone and in turn set the light and it will go off in a mile or so. I have a "Boost Annihlator" from ITP. Your MAP sensor is what sees the boost that causes the light and this device goes inline to your MAP sensor and prevents the sensor from seeing any boost levels above 22psi or you can adjust it therefore no more engine light. It works well!