Manifold Absolute Pressure Sensor
WARNING: This page is about a different car, the 2013 Infiniti M56. However, it is still accessible from the selected car via links, so may be relevant.
The manifold absolute pressure (MAP) sensor is installed on the intake manifold collector. Detects intake manifold pressure, and transmits a voltage signal to the ECM.
The sensor uses a silicone diaphragm which is sensitive to the change in pressure. As the pressure increases, the voltage rises.