Faulty mass air flow sensor
Intake air leaks
Dirty mass air flow sensor
Dirty mass air filter
Mass air flow sensor harness is open or shorted
Mass air flow sensor circuit poor electrical connection
Engine Light ON (or Service Engine Soon Warning Light)
Engine running rough
Excessive fuel consumption
The Mass Air Flow (MAF) sensor is placed in the stream of intake air. It measures the intake flow rate by measuring a part of the entire intake flow. It consists of a hot film that is supplied with electric current from the Engine Control Module (ECM).
The temperature of the hot film is controlled by the ECM a certain amount. The heat generated by the hot film is reduced as the intake air flows around it. The more air, the greater the heat loss. Therefore, the ECM must supply more electric current to maintain the temperature of the hot film as air flow increases. The ECM detects the air flow by means of this current change.