Manifold Pressure/Vacuum Sensor: Description and Operation

Description

Manifold Absolute Pressure Sensor (MAPS) are installed on the surge tank (MAPS #1) and the intercooler outlet pipe (MAPS #2) and sense pressure in front of the throttle body and pressure in intake manifold. It calculates mass air flow indirectly (Speed-density type) and transfers this analog signal proportional to the pressure to the ECM. The ECM calculates the intake air quantity and engine speed based on this signal.
This MAPS consists of a piezo-electric element and a hybrid IC that amplifies the element output signal. The element is silicon diaphragm type and adapts pressure sensitive variable resistor effect of semi-conductor.100% vacuum and the manifold pressure apply to the both sides of it respectively. That is, this sensor outputs the silicon variation proportional to pressure change by voltage.