Barometric Pressure Sensor: Description and Operation

Fig. 34 Atmospheric Pressure Sensor And Voltage Chart:

The PA sensor, mounted just above the ECU on the passenger floorboard, is a silicon diaphragm type strain gauge sensor. It converts atmospheric pressure in the intake manifold to an electric signal and inputs that signal to the ECU. This signal is used by the ECU as a reference signal, and compares it to the signal from the MAP sensor to more accurately calculate the engine load condition.