Impreza WRX Wagon F4-2.0L DOHC Turbo (2002)
Manifold Pressure/Vacuum Sensor: Description and Operation
The pressure sensor is attached to the top of the throttle body, and continuously sends to the engine control module (ECM) voltage signals that are
proportional to intake manifold absolute pressures. The ECM controls the fuel injection and ignition timing based on the intake manifold absolute
pressure signals in addition to other signals from many sensors and other control modules.