Map Sensor: Description

The MAP sensor mounts to the intake manifold (Fig 1).

Fig 1: Locating Manifold Absolute Pressure Sensor

Courtesy of DAIMLERCHRYSLER CORP.

The MAP sensor signal is provided from a single piezoresistive element located in the center of a diaphragm. The element and diaphragm are both made of silicone. As the pressures changes the diaphragm moves causing the element to deflect which stresses the silicone. When silicone is exposed to stress its resistance changes. As manifold vacuum increases, the MAP sensor input voltage decreases proportionally. The sensor also contains electronics that condition the signal and provide temperature compensation.