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Boost pressure control

Boost pressure control


Boost pressure control is based on engine speed and the available fuel quantity. The control module calculates the air mass that is required to attain the requested torque. Information on the available air comes from the mass air flow sensor. The VNT turbo rail is then regulated so that more or less air enters into the cylinder.

Current boost pressure and current atmospheric pressure

Boost pressure is measured by the charge air pressure sensor (603) in the intake manifold and is filtered before being passed on to the control module.

The atmospheric pressure is measured by the atmospheric pressure sensor, which is mounted in the engine control module. The charge air pressure sensor protects against high pressure and pulsation in the intake manifold.

The atmospheric pressure sensor detects the current atmospheric pressure and informs the control module, which takes the necessary action. Low atmospheric pressure increases the turbo pressure and high atmospheric pressure reduces the turbo pressure.

Boost pressure control

The frequency is regulated when the following conditions have been fulfilled:


- No system faults (DTC) related to the mass air flow sensor, EGR or turbo control.


The desired boost pressure is sent as a PWM signal to the wastegate. The control rod vacuum box also contains a potentiometer to keep track of the control rod position and informs the ECM. Thanks to this potentiometer, the regulation always takes place rapidly and precisely.