Aver ndiaz, the light of Check-Engine is turned on to reveal the preciousness of some failure in the fuel injection system, this can be a large sea of factors, the scanner gives you an indication of where to look for although it may not be right, it is unveiled attentive to the system to be able to perform some repair, depending on the vehicle's brand, it can be a lime. Scaner, if you have the code we can help you, if you do not have it enough to tell us what the code said, that is, oxygen sensor, of tenneath, IAC valve, TPS sensor, etc. You can also inform you of a rich or poor product of a bad combination according to an air leakage either by a scarce or an ecsse ecsse, this does not necessarily have to do with a sensor, but avitually if it is a fault of any, digos that makes, how much you spend or some more details to help you.