The Mass Air Flow (MAF) sensor directly measures the amount of air flowing into the engine. The sensor is mounted between the air cleaner assembly and the air cleaner outlet tube. The sensor utilizes a hot wire sensing element to measure the amount of air entering the engine. The sensor does this by sending a signal, which is generated by the sensor when the incoming air cools the hot wire, to the PCM. The signal is used by the PCM to calculate the injector pulse width, which controls the air/fuel ratio in the engine. The sensor and plastic housing are integral and must be replaced if found to be defective. The sensing element (hot wire) is a thin platinum wire wound on a ceramic bobbin and coated with glass.
This hot wire is maintained at 392°F (200°C) above the ambient temperature as measured by a constant "cold wire''.
A faulty MAF sensor due to loose connections, bad grounds, high resistance in the circuit, or opens in the circuit can cause the following symptoms.
The mass air flow sensor hot wire sensing element and housing are calibrated as a unit and must be serviced as a complete assembly. Do not damage the sensing element, or possible failure of the sensor may occur.