General Information
Component Location
General Description
The amount of intake air flow must be inputted to PCM in order to determine the fuel injection quantity. MAPS (Manifold Absolute Pressure) calculates the amount of air indirectly as measuring the pressure inside of intake manifold. This mechanism is also called 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. MAPS is mounted on surge tank to measure the pressure inside of intake manifold, and it consists of a piezo electric element and hybrid IC which amplifies output signal from the element. A piezo electric element is a sort of a diaphragm using piezo electric effect. One side of the diaphragm is surrounded with vacuum chamber while intake pressure is applied to the other side. Thus, signals are output by the transformation of diaphragm according to the change of pressure inside of intake manifold.
DTC Description
Checking output signals of MAPS under detecting condition, if an output signal is intermittently above 4.5V., PCM sets P1106.
DTC Detecting Condition
Specification
Schematic Diagram
Signal Waveform