Controlling Turbocharger Boost Pressure

When ECM determines that a higher boost pressure is permissible, the boost pressure control valve opens further to pass a portion of the exhaust gas through to the turbocharger inlet. In this way control pressure is reduced, the boost pressure control valve opens later and turbocharger pressure can increase. The ECM controls the turbocharger control valve by grounding one of the terminals with a fixed frequency where the signals duty cycle determines how much he valve should open and therefore how much boost pressure can increase.