6.7L Power Stroke – Wastegate Control Solenoid

The PCM provides a duty cycle to the solenoid which changes the vacuum flow to the actuator causing the wastegate to open and allow exhaust gases to bypass the turbine.
The wastegate helps maintain the required intake manifold pressure.
It is used when mostly when intake manifold pressure needs to be decreased quickly. When the wastegate is opened, exhaust back pressure is decreased, reducing the turbocharger turbine speed.