Manifold Absolute Pressure (MAP) Sensor
WARNING: This page is about a different car, the 2007 Mercury Mariner and 2007 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
The MAP sensor uses a piezo-resistive silicon sensing element to provide a voltage proportional to the absolute pressure in the intake manifold.
The MAP sensor is part of the exhaust gas recirculation (EGR) system. The PCM uses information from the MAP sensor, throttle position (TP) sensor, mass air flow (MAF) sensor, cylinder head temperature (CHT) sensor and crankshaft position (CKP) sensor to determine how much exhaust gas is introduced into the intake manifold.