Denso MAP Sensor – Air Pressure & Altitude Adaptation (DAP-0109)

The MAP sensor detects the intake manifold pressure downstream from the throttle valve in order to indirectly calculate the intake air volume based on the relationship between pressure and engine rotational speed. 

The MAP sensor is a compact semiconductor vacuum sensor that utilizes characteristics (piezoelectric resistance effect) whereby electrical resistance changes when pressure is applied to silicon (single crystal). Thus, the MAP sensor inputs intake manifold pressure to the engine ECU in the form of electric signals.The intake air volume is then calculated from these electric signals for accurate air-fuel ratio control.