9-3 Convertible (9400) L4-2.0L Turbo (2.0 HOT) (2003)
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Manifold Pressure/Vacuum Sensor: Description and Operation
Manifold Absolute Pressure Sensor
Inside the pressure sensor there are two metal-plated ceramic discs mounted close together. The disc situated closest to the pressure connection is thinner
and bends when exposed to pressure. This changes the capacitance between the metal-plated discs depending on the pressure. Integrated in the sensor is
a circuit that converts capacitance to analogue voltage. The pressure sensor is screwed to the intake manifold on the engine after the throttle and is
powered with 5 V from control module pin 69 and grounded from control module pin 22.
Depending on the pressure in the intake manifold, the pressure sensor delivers a voltage to control module pin 11.
During rapid load changes, the engine load or calculated air mass/combustion based on the mass air flow sensor value can differ from the actual air mass
