General Information: General Description

In order to determine the correct amount of fuel, the PCM uses the MAP to help determining the amount of intake air flow. To measure the air flow in the intake manifold, the MAFS is used at idle and MAPS is required during accelerating. The MAPS (Manifold Absolute Pressure) calculates the amount of air indirectly as measuring the pressure inside of intake manifold. This system is called a Speed-Density type. MAPS transfers analog output signal which is proportional to the change of intake manifold pressure, then, with this signal and RPM, PCM calculates the amount of intake air flow. The MAPS is mounted on the surge tank to measure the pressure inside of intake manifold, and it consists of a piezo electric element and a hybrid IC which amplifies the output signal from the element. A diaphragm with a piezo electric element is use to convert pressure into voltage. One side of the diaphragm has a chamber with a fixed (absolute) pressure while intake pressure is applied to the other side. As the intake manifold pressure changes, the diaphragm moves which changes a voltage output.