Scion 22204-22010 Intake Air Flow Meter Sub-Assembly

The MAF sensor is located on the air filter housing with a platinum hot wire, thermistor and control circuit inside a plastic housing. This sensor makes use of a sensing element (hot-wire) to check the molecular mass (weight) of intake air into the engine. As the throttle opens, more air passes over the hot wire, thereby cooling it down. The function of this MAF sensor circuit is to retain the hot wire at one unaltered preset temperature by managing how current flows through it. As it cools down, PCM augments current through this hot wire in order to maintain its temperature at that particular degree. The voltage signal output from the MAF sensor fluctuates depending on this flow of current. This signal is then converted into digital waveform by PCM that calculates fuel injector pulse width (duration), turns injectors on and off correspondingly. Any trouble in such sensor circuit will activate diagnostic trouble code. Assure key ignition is OFF; remove electrical connector from MAF sensor; take out two screws holding sensor-take off both O-ring plus MAF sensors from housing air filter; fit new O-ring before reinserting them and reverse installation process.