Manifold Pressure/Vacuum Sensor: Description and Operation
Manifold absolute pressure (MAP) sensor, turbo -M90The manifold absolute pressure (MAP) sensor is mounted on a bracket located on the left under the dashboard and connected to the intake manifold after the throttle. The sensor is supplied with 5 V from control module pin 20 and grounded via control module pin 17.
Depending on the pressure in the intake manifold, the pressure sensor applies a proportional current to control module pin 14. The control module uses this current to control boost pressure.
From M91 the pressure sensor has been replaced by an intake air temperature sensor. Prevailing boost pressure is calculated on the basis of the load signal from LH and corrected with the temperature of the intake air.