9-3 SE Sedan (9400) L4-2.0L Turbo (B204) HO (1999)
Absolute Pressure Sensor: Description and Operation
Trionic T7, 4-Cyl
Charge Air Absolute Pressure Sensor (603)
Pressure given in kPa refers to absolute pressure, i.e. 100 kPa represents atmospheric pressure at sea level.
When checking the pressure sensor with a pressure/vacuum pump, slightly lower voltages may be obtained at high altitudes.
Charge Air 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 connected with a hose to the intake manifold on the engine after the
throttle and is powered with 5V from control module pin 46 and grounded from control module pin 70.