Absolute Pressure Sensor: Description and Operation

Atmospheric Pressure Sensor (Integrated into Control Unit)
Depending on altitude or atmospheric pressure, the atmospheric pressure sensor influences EGR volume. The atmospheric pressure sensor sends the control unit a voltage signal which is proportionate to the atmospheric pressure (i.e. low voltage at low pressure). In other words, the control unit determines EGR volume according to the relative atmospheric pressure via a reduction in vacuum transducer current.