Manifold Absolute Pressure Sensor (MAPS) is a speed-density
type sensor and is installed on the surge tank. It senses absolute
pressure of the surge tank and transfers the analog signal proportional
to the pressure to the ECM.
By using this signal, the ECM calculates the intake air quantity and engine speed.
The MAPS consists of a piezo-electric element and a hybrid IC
that amplifies the element output signal. The element is silicon
diaphragm type that adapts pressure sensitive variable resistor effect
of semi-conductor.
Because one end of the silicon diaphragm is 100% vacuum and
the manifold pressure applies to the other end, the sensor output can be
achieved in analog signals from the silicon variation proportional to
pressure change.